Well a lecture hall isn't really a regular pickup scene for me. I think that anyone who is a sociable enough person won't rush things when it comes to gaming girls in your class. There are tons of oppurtunies to build rapport and when you have something going on in your life (Hopefully your trying to be a DJ and not just a PUA, then you'd have a life) just ask if she'd like to come along. That's not too embarrassing to do, right? Just be patient yet persistant and something will come out of it. Talking to girls all the time is a win/win situation because even if she doesn't agree to go out with you all the other girls in the class will see you constantly talking to a girl. They'll begin to feel more comfortable in your presence and therefore be more receptive to you opening them.
That's my advice, if you feel better just number closingdo what everyone else says and get over the fear by practicing on girls out of class.