scrapster- i never lay off the herb and i get more ass then a toilet seat man =]
anyways...er..here is my suggestion.
In my obvervations, adventures andtravels. I find that each guy has to have his own approach. You cannot just take some cheesy pick up line or stunt off some web site or maxim (sigh..) and expect it to work. What is this apporach? Basically it is magnifying a part of you that you are proud of. Maybe its your b1tching biceps, maybe its your candlelit poetry readings. I can't tell you this, only you can figure that part out. What this apporach bs translates into is BEING YOURSELF. Even though you hear that sh1t from your grandma, thats the key. The approach is just a way of magnifying a good quality you think you posses.
Secondly, you need to get comfortable talking to women!!!! Perhaps you are too shy to approach this babe in class straight up, so what you should do is just strike up some friendly chit chat with girls that you are not interested in. This is a lot easier because since your not interested in them, you dont really care about rejection. After you actually *talk* to some women (yes, yes, some guys really do this). You will become more comfortable, appear more confident, which is a very attractive quality.
Now...i know you will just disregard all this advice I gave you and sit at home for the rest of your life wondering "what if". But..just in case you actually approach her (which you wont, but feel free to prove me wrong)..do not go up with a serious, long term realitionship on your mind. Just make some nice, friendly conversation to pass the time. You are not trying to get into her pants (right now anyways ), you are not asking her to marry you, you are just making some light conversation. Let it go from there, you should be able to read how she responds to you from there.
So, let's recap
Be yourself
Talk to her
Now i hear you saying to yourself "but it's not that simple!!! I'm shy!!!".
Yes, it is that simple godammit. I used to be a shy little sh|t like you and hated it, and at any given second you can change it for the better! Just do it man, or chalk up another regret and missed oppurtunity for happiness and fun.
but its up to you...