Star Wars Knights of the Old Republic 2: The Sith Lords
Kill Darth Sion without a Scratch:
Anytime in the game when you get to choose force powers, choose Saber Throw. Upgrade it to the last form which is Advanced
Lightsaber Throw. When facing Sion, just keep running around him using Saberthrow. It will get the job done.
On the Ebon Hawk after you spar with Handmaiden she won't be wearing any clothes. Dress yourself, then tell her to put some on. You can sell these robes and repeat the process indefinitely.
After beating Mira or Hanharr, exit the pit through the door then go through another door on the left. After you go through this door and defeat the enemies within, walk into the wall directly opposite the door you just came through and press A when your reticule turns blue.
Find the broken speeder in the refugee camp on Narshadaa and install a navigation interface (you can buy one from a droid vendor). Don't repair anything else or install any other parts. You should get 400 exp and the navigation interface back. Rinse, wash, repeat.
Endless light side points:
Everytime you talk to the last handmaid in the Jedi base on Telos you'll gain light side points, so long as you don't say anything rude.
Endless dark side points:
Play up until you get to the Citadel Station on Telos. You must get to the Ithorian Compound there
and play until the Mercenaries try to take it over. Fight all of them until you get to Chodo Habat's assistant, Moza.
Tell him that the Ithorians will need to fend for themselves and be sure not to accept the passcard.
Talk to Moza again and he will act like nothing is wrong. Do this repeatedly to get infinite Dark Side points.
Bonus dialogue options:
Beat the game twice; once with a lightside character and once with a darkside character and then play through a third time.
Against droids, containers, and locked or busted doors the plasma torch is indispensable.
Get New Items from Merchants:
First you must find a merchant. When you do, save your game before speaking to him or her. After saving, speak to the merchant.
If they have nothing you desire, press start. Then select Load Game on the options menu and load the game you just saved.
Talk to the merchant again, and boom! They will have different items in stock.
Special thanks to Revolution readers Danny, BCGrobal, Hawkmoon2, Kryuhkin, -=Code-Red=-, and Brian Sampson!