What is the best way to start a converstation with a girl you like?

First I would start with the basic what's up and get to know her. Then once you think it's right ask her. You will be find im sure. honestly, as a 16 year old girl, I would say the best was is to just say hey! If you have any classes together, then you have some common ground. If you see her in the library or something, casually ask if she has done the homework, or how she found the test. Or if you have absolutely no connections with her, but just admire her from afar, then find out what she is involved with at the school (clubs etc..) You can either A) join them or B) ask her about them. Or you could go to the same parties that she would go to, which is a great place to introduce yourself. Or find a connection with a mutual friend/acquaintance. One tip: don't creepily add her on facebook when you have never spoken to her. Then when she does meet you she will probably remember you as the facebook stalker who added her.... not the best rep. The opportunities are endless! Just make sure you are friendly and smile. Pretend to be outgoing even if you are not!