How come I can't get just one girlfriend?

So I was at a county fair today hoping to maybe get a number or two from a nice and attractive girl, because I wanted to see if I could finally reel one in, just once...but of course I couldn't once again. Usually I just let them come to me, and I came so close by doing that today with a beautiful girl who seemed to have followed me and my friend around, she even got on a ride with us alone. But she didn't say anything to me so I wasn't really sure if she liked me or my friend at all because after the ride she walked off with her friends. Since I blew it this time, I want to ask for some advice on how to do better the next time around (im going back to the fair monday). Just how can I be more confident in these situations, because right now i'm not at all...