Just have confidence when you approach them. A couple ways to achieve confidence, (some people might say this is a superficial and materialistic list but it does help), get yourself a fresh hair cut, wear an outfit that you feel you look good in, make sure you get ready before you leave your house, clean yourself up nice, wash your face, put on a nice smelling cologne, make sure when you look in the mirror you're like "Damn I look good today". Ok now that you got the appearance down, remind yourself about all the qualities you have that would make a female interested in you, so you know you're a worthy bachelor for any broad!

Now that you're feeling confident, make sure your approach is real smooth, try to come from the corner it's better to approach a girl from the side than it is to approach her directly head on it's less threatning, more subtle. Open up with something that will break out into more conversation so you can get a nice foundation set up. I.E. "I like your outfit it looks good on you", "I haven't really seen you around often what part of town are you from?", "Don't I have this class with you..." etc... From there just be witty and try to make her laugh but don't go crazy. Just be smooth and keep it low key like sea shells.

When you're done conversing, tell her you enjoy her company and would like to talk with her more. This is where you ask for her telephone number. From there you work your game champ!

I hope everything works out.