What follows is a simplified, step-by-step walkthrough of the game that will help you progress in the most efficient manner (minimal running around). Refer to the specific pages for each world to find how to complete individual steps. I start with Taris, as Endar Spire is self-explanatory (it is the tutorial after all).

To Do List

1. Return to your hideout/Ebon Hawk as often as possible to heal and talk to your companions (especially after a level up).
2. Rotate party members to help advance their interpersonal dialogue. Leave Ebon Hawk with every party member when first arriving on a world and immediately after finding the Star Map on a world.
3. Hold your loot until you get to Yavin Station. Suvam Tan pays more for items than any other merchant.
4. Avoid buying items as much as possible. Make use of the free stuff your companions will make for you on Ebon Hawk (grenades from Zaalbar, computer spikes from T3-M4, stimulants from Canderous, medpacks from Jolee). Live off your loot. You want to maximize your cash for a spending spree on Yavin Station right before heading to Star Forge.

Taris

1. From your apartment, exit to Upper City South and head directly across to Kebla's shop. Light Side: buy a permacrete detonator (50cr). If you need money, sell some of your loot (normally, you would hold on to as much loot as possible to sell for higher prices later).
2. Go to the cantina and meet with either Sarna or Yun Genda to get a party invitation. Go to the dueling arena, you should be able to beat the first two competitors easily at this point. This will provide you with some extra cash.
3. Go to the medical facility and get the rakghoul serum quest from Zelka.
4. Head for Upper City North, stopping to help (or hurt) the old man being shaken down by Davik's thugs.
5. Once in Upper City North, head to the North Apartments and go to your party and get your Sith armor. If you couldn't swing the invite, get the Sith armor off one of the soldiers threatening an Ithorian in one of the other apartments.
6. Go to Lower City, make sure to equip the Sith armor before approaching the guard at the elevator.
7. Go to Javyar's cantina and get bounty hunter quests. If playing Light Side, Persuade or bribe Holdan to cancel Dia's bounty.
8. Go to Bek base and exchange Sith armor for papers.
9. Go to apartments #1 to loot (Echani Fiber Armor!) and take care of Matrik (this is where the permacrete detonator is needed if playing Light Side).
10. Go to apartments #2 to loot (Republic Mod Armor!) and kill Selven.
11. Go back to Javyar's and collect on Matrik's and Selven's bounties.
12. Go to Undercity and get rakghoul serum and Rukil's apprentice's journal from the area outside the village.
13. Enter the Lower Sewers and rescue Zaalbar. Collect the other two Promised Land journals.
14. Return to Undercity and the village. Light Side: help the diseased villagers with the serum and then give the Promised Land journals to Rukil. Dark Side: sell the journals to Igear.
15. Back to the Lower Sewers and enter the Upper Sewers. Head straight through, deal with rancor beast and enter Vulkar base.
16. Complete Vulkar base using my guide.
17. Exit Vulkar base to Lower City and go to Bek base. Agree to race the Bek's swoop bike. Dark Side: kill Gadon Thek instead.
18. Rescue Bastila and return to hideout. After getting the message from Canderous, pick the lock on Dia's door to kill her for the bounty or inform her you have bought Holdan off.
19. Go to Upper City cantina to meet Canderous and complete the dueling arena matches. Dark Side: engage Bendak Starkiller in a deathmatch and finish his bounty.
20. Light Side: Go to medical facility and give Zelka the rakghoul serum.
21. Go to North Apartments and either kill Largo for his bounty or (Light Side) buy off his bounty (200 credits).
22. Head to droid shop and buy T3-M4. Head straight back across to Sith base entrance and T3-M4 will open the door.
23. Complete Sith base and go to Javyar's cantina and inform Canderous. Go see Zax to collect any outstanding bounties and (Dark Side) sell him the rakghoul serum.
24. Travel with Canderous to Davik Kang's estate and complete your escape from Taris.

Dantooine

1. Follow the story to be accepted as a Jedi and given the quest to cleanse the taint from the sacred grove.
2. Head to the Courtyard and talk to Jon and Elise. Avoid buying stuff from Adum Larp, you'll get better items later.
3. From Courtyard, take the west-most exit to Matale Grounds. Deal with the Mandalorians nearby.
4. Exit to Grove using the west-most exit and then travel east. You'll meet Bolook on the bridge, so stop and investigate the murder.
5. Continue travelling east. Deal with the Mandalorians you will find. Circle around as many kath hounds as you can to get to the grove, and take care of Juhani.
6. Transit back to Enclave and visit the Council. You'll get the Investigate Ruins and Sandral-Matale Feud quests.
7. Transit back to the Grove and head north to the Matale Grounds. Find Casus' body and collect his journal.
8. Head straight south until you reach the Sandral Grounds. Find Elise's droid and take care of the situation. Enter the crystal cave and collect lightsaber crystals.
9. Go west and kill the Mandalorians. Watch out for the albino kath hound.
10. When you reach the Sandral estate, finish the Feud quest.
11. Now head north to the Grove and then go east to find the Mandalorian commander.
12. Transit back to the Enclave and exit to the Courtyard. Speak with Jon and Elise again to finish their quests. Then go east to the ruins. You need to have Bastila with you when you go to the ruins.
13. Complete the ruins and find the Star Map. Transit back to the Enclave.
14. Visit the Council to be sent on the search for the Star Forge. If you told Elise her droid had to be destroyed, go to the north rooms and speak to her about her new boyfriend. This will officially complete her quest.
15. Board Ebon Hawk and travel to Yavin Space Station.

Yavin Space Station (First Visit)

1. After arriving at Yavin, Zaalbar will inform you someone has been breaking into the stores. Find the stowaway and (Dark Side) force her off the ship. Otherwise, just leave her alone.
2. Visit Suvam Tan on the station.
3. (Light Side) Head back to Dantooine and return Sasha to Lur Arka. Take Mission with you when you exit the ship and meet Lena to continue the Mission's Brother quest.
4. Travel to Kashyyyk.

Kashyyyk

1. After paying the port fee, visit Eli and Matton to get the Honest Debt quest.
2. Travel the Walkway to Rwookrrorro and meet with Chuundar.
3. Head down to the Shadowlands--you'll run into Calo Nord at the bottom of the lift. Make sure you have plenty of grenades.
4. Follow the path until you meet Jolee. After Jolee asks you back to his camp, search the surrounding area until you find a Wookie corpse with a slaver's datapad and a blaster bolt casing on the body.
5. Talk with Jolee about the poachers.
6. Go south until you find the destroyed droid and retrieve its head.
7. Head back up to the walkway and return to the village.
8. Go to the Holder of the Laws and show him the blaster bolt casing. Deal with the trial in whatever manner seems fit to you: (Light Side) reveal the information Rorworr was dealing with slavers; (Dark Side) let Jaarak take the fall.
9. From the village, transit back to the landing port and inform Matton of Eli's treachery.
10. Head towards the walkway with Bastila in your party, and you'll meet Malare, who will inform Bastila her mother wants to see her and is waiting on Tatooine, thus kicking off the Bastila's Mother quest.
11. Find the poachers' camp and clear it: (Light Side) Persuade guards to turn off their sonic emitters; (Dark Side) kill the poachers. Make sure to collect some tach glands from one of the storage boxes.
12. Return to Jolee and he'll join your party. Go to the Lower Shadowlands.
13. Help Grrrwahrr defeat the Mandalorians and then (Light Side) help him out with a medpack. He'll tell you of the Mandalorian raiders.
14. Head southwest and find the first group of Wookie bodies. Unequip your weapons, power up and keep walking. Mandalorians will appear. Re-equip weapons and dispatch them.
15. Go southwest and then south to find the second group of Wookie bodies. Repeat step (14).
16. Travel northwest to find the Mandalorian swoop bikes and replace the signal generator on one of them. The Mandalorian leader will uncloak and you can take care of him.
17. Go south to find the Star Map.
18. Follow my map to point (E) (basically: north, northeast, south, east, south some more) and kill the terentatek. Collect Bacca's sword blade.
19. Find Freyyr and either (Light Side) give him Bacca's blade so he can lead a revolt against Chuundar; or (Dark Side) kill him.
20. On your way out of the Shadowlands, stop and speak with Grrrwahrr to complete his quest.
21. Return to the village of Rwookrrorro and finalize the situation. Whichever path you choose, Zaalbar will rejoin you, now with a nice, upgradeable sword (Bacca's) in hand.
22. (Light Side) After returning to the port, travel through the area helping the Wookie's dispatch the evil Czerka.
23. Travel to Korriban

Korriban (Brief Visit)

1. Go see Lurze near the cantina in Dreshdae and deal with the spice on your ship. Accept a commission to deliver a box to Motta the Hut on Tatooine.
2. Leave for Tatooine.

Tatooine

1. Exit Ebon Hawk with Jolee in the party to get the news about Sunry on Manaan. If you haven't met Lena yet, have Mission in your party. If you haven't gotten the Bastila's Mother quest, include Bastila in your party and you'll meet Malare.
2. Buy bantha fodder and gizka poison from the merchant in the docking bay.
3. As soon as you are informed you have received a shipment of gizka, re-enter Ebon Hawk and poison one of the gizka.
4. Go into Anchorhead and take care of Sharina: (Light Side) buy her wraid plate and throw in 200 extra credits; (Dark Side) force her to give you the wraid plate.
5. Enter the Czerka office and speak to the protocol officer. Ask about getting a hunting license and about Griff.
6. Once you have the hunting license, enter the Hunting Lodge to sell Sharina's wraid plate for 500 credits.
7. Go east until you are ambushed by dark jedi. After dispatching them, turn into the Swoop Registration office and fulfill your commission to deliver the box to Motta the Hut. Engage in swoop racing, if you like. If you have a high Persuade skill, can win all three tiers of racing and want some Dark Side points, accept the job from Motta to convince Niko to sign a bad contract.
8. Exit Swoop Registration and continue east to the cantina. Inside, meet with Bastila's mother (with Bastila in your party).
9. Go north to the droid shop and buy HK-47.
10. Head for the city gate and talk to Iziz the Jawa nearby, then exit to the Dune Sea.
11. When you first enter the Dune Sea, meet Marlena Venn and find out about Tanis. Go south and a little east to find Tanis and his droids and either (Light Side) help him or (Dark Side) leave him to his fate.
12. In the Dune Sea, stick to the middle of the area and avoid going too far towards the edges or you will be ambushed by Sand People.
13. Head straight for the wrecked harvester and fight off three waves of Sand People.
14. Circle around the east side of the harvester and approach the speeder wreckage nearby. Disable any mines in the area. Make sure you are at full health before triggering the trap. Take care of the Gammoreans who pop up.
15. Kill the Sand People clustered around the exit to their area. Take at least one Sand People outfit (for yourself) and one for your other non-droid party member (if you have one).
16. Equip your SP outfits and run through the SP area to the enclave. Once inside, meet with the chieftan and agree to get some moisture vaporators for him (Light Side); or, just kill all the Sand People (Dark Side)
17. (Light Side) Exit the SP enclave and transit back to Ebon Hawk. Enter Anchorhead and buy vaporators from Greeta in the Czerka office. Walk all the way back to the SP enclave (yeah, unfortunately, you cannot transit back...) and meet with the chieftan again. He'll reward you with his gaffi stick.
18. Explore the enclave and free the Jawas and Griff. You can get bantha fodder from a heap of rags near the entrance.
19. Head for the Eastern Dune Sea and collect the Star Map after helping to kill the krayt dragon. Also collect Bastila's father's holocron.
20. Walk back to the Dune Sea and then transit to Ebon Hawk. Return to Anchorhead and visit the Czerka office. Give the chieftan's gaffi stick to the protocol officer to complete your quest. Speak to Griff about his new scheme. Give him the tach glands.
21. On your way to the cantina, you will meet Senni Vek, who will give you a "dropped" datapad asking you to meet someone named Hulas on Manaan.
22. Go to the cantina and help Bastila reconcile with her mother (or encourage them to keep fighting...)
23. Go back to the Czerka office and speak to Greeta to find out Griff has run away again. Speak to Mission about her brother. This is the last useful thing Mission will say during the game (shame too, I kinda like the kid...)
24. If you haven't achieved either Light Side or Dark Side mastery by this point, you're not doing something right...
25. Now it's time for another trip to Yavin IV

Yavin Space Station (Second Visit)

1. Go see Suvam Tan. You'll find him being threatened by Trandoshans, so scare them off. His inventory is now upgraded and he'll buy your items for more as well. But don't sell anything yet unless you're desparate for cash (which you shouldn't be).
2. Leave and travel to Manaan

Manaan

1. If you've been talking with all your companions on a regular basis, you should be at the point in Canderous' conversations where he has promised he will tell you about working for Davik. He won't actually tell you anything more until you finish his quest. Leave the ship with him, and, right as you pass the merchant in the docking ring, you will meet Jagi and he will challenge Canderous to a duel. You could turn around a leave right now (before you pay the docking fee), but there's no real reason not to wait until you finish with Manaan.
2. If, for some reason, you can't bring yourself to poison the gizka, you might be able to unload them on the exotic species dealer in the docking ring.
3. Go into Ahto City and head for Ahto City West. Make sure Jolee is in your party. Meet Elora and learn more about Sunry.
4. Go to the courts and introduce yourself to Judge Shelkar. Ask to investigate Sunry's case.
5. Go to the prison and talk to the guard. He will open the door for you now. Go inside and talk to Sunry to get his account of the murder.
6. Go across the courtyard to the mercenary hangout and get Nilko Bwaas' quest concerning Republic mercenaries and Shaelas' quest to find missing Selkath youth.
7. Head for East Central Courtyard and find Hulas. Send your party members packing before speaking to him. If playing Light Side, turn down his offer to join the Genoharadan.
8. Go north to find the Visitor's Hotel and interview Ignus, Gluupor and Firith Me. You'll need to Persuade Gluupor and Firith to reveal their secret information if you want Sunry acquitted. (Note, there are no Light Side points for getting Sunry off the hook.)
9. Head across to the Republic Embassy and talk to Roland Wann about the Star Map. He'll ask you to recover the data module from a Republic droid captured by the Sith. Agree to do so and ask about the different methods for gaining access to the Sith embassy. If you decide to interrogate the prisoner or hack a passcard, go take care of that now. If you want the truth about Sunry's murder case, hack the Republic computer now. (Dark Side) One of the persons Hulas wants killed is inside. Kill him and then go back and talk to Hulas again to receive the remaining assassination quests.
10. If playing Dark Side, now's a good time to drop what you're doing and go kill the persons Hulas wants killed. While you're at it, you can handle Canderous' duel with Jagi as well. See my description of these quests to find out what to do.
11. If you are interested in swoop racing (total prizes on Manaan are 7500 credits), stop at Swoop Registration in Ahto East and take care of business.
12. Now head for the Sith embassy and raid it to retrieve Wann's data module. When you leave, you'll be taken to court. See the Manaan page for a guide to the base and to the trial. Afterwards, you can finish Sunry's trial.
13. Go back to the Republic Embassy and give the data module to Roland Wann. He'll fill you in on the activity on the sea floor and give you the keys to your very own submersible!
14. Now might be a good time to transit back to Ebon Hawk, speak to all your companions to be sure you are up-to-date on their conversations and upgrade weapons and armor with the workbench. You've got a tough little row to hoe coming up, so be prepared.
15. Take a combat-heavy party to the submersible in the Republic Embassy--there's not much need for computer slicing or lock picking skills down under (the deep blue sea). Follow my guide to complete the Hrakert Station/Rift area and get the Manaan Star Map. Return to the surface and stand trial (again).
16. After the trial, run across the courtyard to the mercenary hangout and report in to Nilko Bwaas. That should wrap things up on Manaan. Transit back to Ebon Hawk.
17. If you've been keeping up with your companion conversations, you should have reached the point where Juhani tells how Revan saved her from the auction block. Exit Ebon Hawk with her and walk through the docking bacy. You'll meet Xor, the Twi'lek who was trying to buy Juhani back on Taris. This will set you up for a later meeting with Xor, where you have to once again save Juhani from herself.
18. Now leave the ship with Carth and you'll meet Jordo who will inform Carth his son, Dustil, is a student at the Sith Academy on Korriban.
19. Enter your ship and target Korriban...

Leviathan

1. After you've been captured, choose Juhani to be the infiltrator (Canderous and HK-47 work well also, but I prefer Juhani).
2. Once Juhani uncloaks, head quickly to the barracks and kill the guards. Get a detention area passcard from a footlocker in the barracks.
3. Go to the detention center (hacking-and-slashing as needed) and free Bastila, Carth and your PC.
4. Now you have your PC again, and Bastila and Carth in your party. Take the elevator to the bridge and chop your way through the command deck to the armory to pick up a space suit.
5. Go to the airlocks and take a little space walk to the bridge. Kill Admiral Karath and then unlock the hangar bay doors.
6. Take the elevator down to the hangar and then take any good equipment away from Bastila :)
7. After your tete-a-tete with Malak, you and Carth will rejoin the others on Ebon Hawk and continue your journey to Korriban.

Korriban (Extended Stay)

1. As you exit Ebon Hawk, you will be met by Ziagrom. This will open the premium items for sale in the cantina in Dreshdae.
2. (Optional) If you are running low on grenades and/or mines, buy some from B'ree at the "visitor's center". You will need plenty of these items for this world.
3. Head straight through Dreshdae and speak to the Sith Academy Guard at the entrance to the academy.
4. (Optional) For fun (and some Light Side or Dark Side points) run back through Dreshdae dealing with various belligerent Sith as you see fit.
5. Go back to the cantina and find Yuthura and speak to her to gain entrance to the academy. Be sure you have the companions you want for this as there's no coming back once you enter the academy.
6. Once in the academy, speak to Yuthura to learn the Sith code and learn of the plot to take down Master Uthar.
7. Go to Uthar and recite the code and answer a question about its meaning. Then tell him of Yuthura's plot and get a datapad to give to Adrenas.
8. Take the datapad to Adrenas.
9. Return to Yuthura and tell her Uthar knows about her plot. Lie about there being anything else. She'll give you a device to put under Uthar's bed and a key to his room.
10. Plant the device in Uthar's room (you have now prepared both Uthar and Yuthura to be weakened during the climactic battle) and make sure you loot a datapad from a footlocker nearby.
11. If you have Carth with you, find Dustil Onasi and use the datapad to convince him to leave the Sith (you don't need to do this, and you're probably better off skipping it as Carth and Dustil argue for about five minutes while you just watch...)
12. Now go through the north exit to the Valley of the Dark Lords.
13. Find the shyrack caves and deal with the renegade students: (Light Side) kill the terentatek and let them escape; (Dark Side) kill the students (you can still kill the terentatek as well). Make sure to get the Qel'Droma robes from the corpse behind the terentatek. (To sell at the very least.)
14. Contine into the Valley and visit the tombs of Marka Ragnos, Ajunta Pall and Tulak Hord.
15. Return to Uthar and mention you have dealt with the renegade students, the rogue droid in Ragnos' tomb and Jorak Uln in Hord's tomb. This will earn you enough prestige to be taken to Sadow's tomb for the final test. (And, as a bonus, you will get to keep Ajunta Pall's sword, which is an excellent weapon for any non-Jedi melee fighters in your group.)
16. Complete the quest for the Star Map in Naga Sadow's tomb. Kill both Uthar and Yuthura, or just one or the other on your way out.

Canderous and Juhani

1. If you want to solve Canderous' and Juhani's problems, head for Tatooine to meet Jorgi in a duel with Canderous. Finding Xor is more difficult. As best I can determine, his appearance is totally random (and somewhat senseless). For example, I've encountered him on Kashyyyk with a couple of Czerka Thugs even though I had played Light Side and helped the Wookies expel all outsiders from Kashyyyk!? The best you can do, if you want to complete Juhani's quest, is keep hopping around and leaving the ship until he shows up.
2. Head for Yavin Space Station.

Yavin Space Station (Third Visit)

1. When you enter Suvam Tan's "shop", you will be attacked by Trandoshans. This is a tough fight, so power up before you enter Tan's hideaway. Once you have defeated them, you will get the full range of items from Tan. Now is the time to go hog wild. Sell him all your accumulated loot (he pays very well) and buy to your heart's content. You're not going to get another chance to visit a merchant in the game, so there's no point in saving any credits. Especially nice are two lightsaber crystals (Mantle of the Force and Heart of the Guardian) that are used in the "color" crystal slot of your saber. They enhance the abilities added by the other crystals. There are also a couple of great assault weapons for whichever member of your party is using heavy weapons or blaster rifles (such as Canderous or HK-47) and some really good armor for Mission. Don't forget the unlimited-charge items for HK-47 if you plan to use him heavily.
2. Once you have shopped 'til you dropped, enter Ebon Hawk and target the Star Forge System.

Unknown World

1. As you leave Ebon Hawk, you'll be set upon by Rakata. Take care of them and head east to deal with their buddies.
2. Go to the Temple Exterior and fight some rancors. Sidle around the western edge to the South Beach exit. (Optional) If you're looking for extra experience, deal with the other rancors in this area and depopulate the Mandalorian camp.
3. On the way to South Beach, search the spaceship wreckage for parts for Ebon Hawk. Unless you have an extremely high Awareness skill, you're going to trigger mines, so just be prepared and step slowly (so you don't hit too many without pausing to heal). If you've been maxing Mission's Demolitions/Awareness skills (which you should have been doing) equip her with a boosting item and she can not only detect the mines, but recover them. They're highly useful later in the One's settlement.
4. Continue to the Elder Settlement and enter. Make a deal with the Elders to rescue one of their scouts.
5. (Optional) Go around the eastern side of the settlement to the first room. Inside, meet with Ll'awa to receive the quest for genetic records.
6. Outside the settlement, transit back to Ebon Hawk and then head for North Beach.
7. Kill the Rakata and rancors outside the One's settlement and enter. Go east and then north for your meeting with the One.
8. After passing over the bridge, in the long corridor leading into the One's chamber, lay down a bunch of mines. (The Deadly Plasma Mines Mission can recover from the wrecked ship site are very nice). Enter the One's chamber and, after he opens the cages, run back down the corridor so he and his pet rancors get the edge taken off by the mines.
9. Speak to the Elder prisoner and collect ship parts for Ebon Hawk.
10. Return to the Elder's Settlement and let them know you are ready to enter the temple.
11. Go to the Temple Exterior alone. Jolee and Juhani will show up mid-ritual and join you.
12. Once in the temple, go to your right (south) to the computer room and slice the computer (if you have a decent Computer Use skill). Definitely open the Armory door.
13. Travel along the south corridor, killing anything that moves and looting everything you can.
14. Once you get to the Eastern Guard Room, destroy the droids and head down to the catacombs.
15. Follow the map to visit the Rakatan computer so it will open the doors to the Temple Summit for you. Don't miss a lightsaber crystal (Sapith, I think) in an obelisk in the little chamber to the south.
16. Back up to the main floor and head north. Repeat the steps of killing and looting through these rooms. You should find the Upari crystal in one of these rooms. In the Armory is a workbench where you can upgrade your saber(s).
17. Destroy the droids in the Western Guard Room and go to the Summit.
18. Meet with Bastila and either (Light Side) try to turn her back to the light (she'll run away); or (Dark Side) demand her allegiance to you (she'll give it and then the two of you will fight Juhani and Jolee).
19. Return to Ebon Hawk (Dark Side: kill party members who won't join you in your war of conquest against the Republic) and target Star Forge.

Star Forge

1. This is a pretty straightforward and linear area. Just follow my maps and finish the game!
2. Go re-introduce yourself to family and friends.
3. Start up a new game!