I know the feeling. I've been really wanting a girlfriend as well, but the best thing to do is wait for the right one. You don't want to just choose anyone. Get to know some girls, and once you start to have feelings for one of them, or if you know someone, maybe start to flirt just a little bit, and see how she reacts. If she doesn't like it, then don't push it. If she does, start to flirt with her more, and see if she flirts back, or likes it. After a while, tell her how you feel about her, and take it from there :)
Woah...don't be desperate...getting a girl requires patience. Be nice, friendly, caring, sweet, being outgoing, don't be shy, be humorous, basically...be a good person Also...have confidence Good Luck!