Dear Nerdy,
Okay, hold it, if you can't even think of something to start a conversation about you need to take this really slowly. It's not gonna happen over night and if you push too fast she may only be turned away. That is if she only see's you as someone from the "geek" or "nerd" group. First, you need to make sure you have some sort of similar interests otherwise the whole thing is pointless, dates being akward and such, the only comfortable time the two of you have is when you're doing it doggy style on her parent's bed cause you don't have to look at each other. Do not stalk her though, this is also bad. Put simply what have you seen her do out of school, extra cirricular activities and such. If she always hangs out with a crowd you're not comfortable with it may be hopeless for now, let's face facts. Okay, so the first conversation will probably be quick and she may not even realize where it's goin. It'll be just some random converstation to try and get to know her, see if the two of you will really click. That is where i'll leave it up to you, it has to be natural and comfortable for you. Maybe even play it cool like you're just bored and looking for something to do to pass the time. This will also decide if the two of you will ever speak again. After time you may even be able to see what she's doing after school someday and the big step, drum role please, ask her for the digits (her phone number if anyone didn't understand that). From there you could make your move at the right time, get back to us when you get this far though.
Or you could just club her and drag her back to your cave, worked for me a couple of times.