As CassCore says, asking questions and trying things is really the best way to go. There is no one way to pleasure ALL women, so you need to be open about your lack of confidence. If you're open with her, she'll be open with you, and it will be a good experience for the both of you.
The best thing you can do is be open and honest with your partner. Ask her what she likes and what feels good for her. Try different things and take it slow. Let her take your hand and put it where she wants it. Just listen and learn from her. If she loves you she won't expect you to be perfect! She will respect and appreciate you wanting to learn about her body and what feels good for her. ALOT of men don't do that.