1 - School is a better place to meet girls then work, because theres usually more down-time and just a better social atmosphere in general
2 - If you're in class with her, talk to her casually but don't be all lovey-dubby all the time. Communication is important in relationship. So if you can just be around the girl and just talk to her and be comfortable around each other, then you guys got something. And talk to your friends too. Moderation is key. But include your girlfriend with your friends
3 - Walk her to class, hold doors for her, etc. "Gentleman" stuff...
4 - Don't make out with her in the hallways. Don't be that kid.
5 - Also, listen to her talk. Thats another thing. Don't just talk to her. Girls love talking, so listen to her talk about gossip and Britney Spears and other things you probably don't care about, and just respond with simple responses that make her think you care about what she's saying. Like "Damn that sucks" or "Wow thats cool" or "What the hell is up with that". I know that sounds degrading, but it's SO true.