I see a lot of guys here on the forums who suffer from the problem of not being confident enough. as a matter of fact, self-confidence is undoubtedly the single largest sticking point for most guys.
some would call it "inner-game" but I am just going to term it "sc"(short for self-confidence)

sc is achieved by having three things
  1. know your own value. remember your more important to you than any girl. why make a big deal out of gaming one girl who you have clearly placed a higher value on than yourself. you must never place a woman's value over your own. if you think that you may be breaking this rule, think to yourself "what am I doing and why am I doing it, whats in this for me?"
  2. get experience. it is true that more often than not our confidence comes from our experiences. why be afraid of something you've already faced? once you've approached enough girls you simply get to the point where you've seen it all, and believe me, there are only so many tests you can face before you start seeing the same tests over and over again.
  3. don't be attached to an outcome. if you are overly worried about losing the girl, you have already lost her. if you care too much then you will simply get torn apart when you get rejected time and time again. by not caring about how things go, it really won't matter to you when you face rejection.
I know it is harder than it looks to actually follow these rules, but once you get the hang of it, it comes naturally. in this game, you cannot be afraid of failure and you have to maintain that you are the one who has value. this girl you are talking to is the one who is lucky that you are paying attention to her, not the other way around.