Let's see, how to word this... of course you don't have a clue to what she likes or does on her free time.. that is what the purpose of small talk is. You have her in class and if you see her looking at you, it starts as small as smiling back at her. You have common ground that can be used as a conversation - the class. That is your springboard right there. Talk about anything, a paper, a test, a quiz, just take the opportunity to talk to her. Start off small. Look for a way to introduce yourself and just ask her a question and have a very brief conversation and make sure you ask her what her name is, that way you can address her by her first name in the future. Don't hit on her. Just talk to her like she is a friend of yours. Be relaxed and very casual. I think that it is going to be a lot easier than you think and you are a lot smoother cat than you give yourself credit for.