Well if it's an approach with a girl from one of your classes, just start a casual conversation. When I first start talking to a girl, I normally start off with a "Hey, you are in my (--) class, right?"
If she says no, say something such as:
"You sure? First period class with (--) as the professor."
Normally she will be like "Oh yeah!"
After that, follow up with a joke. "That class was so boring, I must have fallen asleep two or three times!"
Than say a couple more lines or two about what other classes she is taking, etc. The most important part is to make sure you start talking to her when she doesn't have to go, etc. This is important because you want to be the one that has to go, not her!
Remember, YOU are the prize. You are a busy person and you have many things to do. Normally after I hit it off with a girl for 3-4 minutes, I put a time restrainer. This is basically where you end the conversation first and let her know you have other things you need to attend too. "Hey listen, I actually have to go right now, couple of people I need to meet; but it was great talking to you! Maybe next time you won't be so chicken and you'll say hi to me."
(Say it with a nice smile on your face, and you are in the game!)
Now, if there is anything I want to end off in my post, it does not matter too much what you talk about, as long as you develop rapport with her. When you talk to her, look in her eyes. Make sure you have good body language: Head up, feet shoulder-width apart, and make sure you are audible!
I have been with a couple of guys and they are trying to hit it off with a girl, and they talk so quietly - don't be scared to be loud! Be charismatic, confident, and try to develop a nice "phone" voice.
There are tons of tips on this site, just try the "Search" feature! If you have any questions regarding my post or have any other questions about this topic, feel free to drop me a PM and I'll be glad to help you out.
Sarge on, and hope I helped.
