I am not too sure about that.
You probably still get to choose other races, just try it out. Kill the boss at level 10. =)
Some good tips, hmm...
Well, if you want to be good, make decisions that a good person would make.
If you want to be evil, make decisions that a bad person would make.
Example:
Here little boy, have a gem= Good deed
Give me your gold little boy= bad deed.
You will spot events which help you in your alignment change, and just travel around and explore places as well.