Maybe you may not be a nerd, but have you considered the people you hang out with to be geeks/ nerds, that affects your appearance believe it or not, if you hang out with funny people than people would consider you funny, or if you hang out with nerds, they consider you nerd, if you hang out with emos, you are considered emo.
Also you are most likely to be shy, if your friends are good with girls, dont be afraid to ask them to hook you up, or maybe if your friend is good friends with another girl you can talk to them, but don't but in with their conversations, you have to like play it smooth, if the girl hangs out with other girls you may want to become friends with that girl and once she trusts you just ask her if one of her friends likes you whatever.
Also girls like when guys have achieved something, so if you have kicked someones ass, girls would most likely think you are tough, if you are the team player, tey will think as you as brave or athletic. For me it's not that hard to get girls because I go to a technology only school, and there are some pretty HOT girls that like technology

so I usually help them if they have trouble. Just don't try too hard because you might make them think you are perverted.
Good luck.