Oh trust me, even with this info you'll probably restart the game a few times from the beginning. You'll get better at it... and much faster, being able to skip through a lot of dialogue and get right back to where you were without much trouble.
One unconditional tip: SAVE OFTEN. I have 5 "temp" save slots at the top of my list, and I use quicksave/quickload all the time, but I keep plenty of saves along the way (there's no limit on them). If I find out I screwed up on the last planet, I definitely have a save file from when I touched down in the Ebon Hawk (at the very least). Definitely save before going Jedi, especially if you saved up a buncha XP and will be leveling a lot. If you change your mind about your Jedi class or the powers you pursue, you don't want to have to re-do all of Taris! (I actually have a save for every level-up, like "SCT 5, SENT 9", so I can step back before any major changes to my character.)
One more tip: Don't allow the game to auto-level anyone, or take feat/power recommendations blindly. It's horrible. A child could make better choices. Take the time to specialize your character & party yourself!
You can get a lot of pointers at GameFAQs, but there's no substitute for first-hand experience: http://www.gamefaqs.com/pc/516675-st...-republic/faqs
If you have any other questions though, I'd be happy to help.