Dude, I kinda used to be in the same thing...what you have to do is just try to forget about it, if you can. Your self-esteem'll be able to come through if your mind is off not having a girl, and they'll see you as more than what you're seeming to be right now.
Just try not to worry about having a girlfriend so much and one'll just fall into your lap.
Then again, this advice might only work for me. I don't know how old James is, for one thing. I'm required to go to school and so are about two-hundred attractive girls. If you don't go to school then it might make it a little harder since you don't see the same person every day and you actually have to make an effort to hunt for them.
But what do I know I'm just a kid
