In reference to preflop betting, it's a good idea (esp starting out) to have a set amount that you are going to raise if you are going to make a raise. A good suggestion is 3-5 times the big blind (ex. when I played NL$25, my standard raise was $0.95 preflop no matter what cards I was raising with...if you get reraised or have a raise in front of you, that changes things - reraise with the big hands; call with the moderately good ones; fold the mediocre).

Hope that helps a bit...let me know if you'd like more detail on this subject.