What opening line should I use?

Most girls like it if you have . If you are able to go "Hey, my name is ____ " i'm sure she'd feel very pleasant and willing to give her name back in return. If this ends here, smile and walk away, this way she will have a reason to think about you more so. If other conversation sparks off this or you feel you could ask something about her (preferably where she's going with this course or something simple like how she is doing). This should go well, it seems like she likes you :) but if you want to play the smiley man, you could do this, just smile at her when she looks at you until you get a good opening or she opens to you, this could take longer but is also a very good approach as long as you don't come off as too hard to get or un interested. Don't let it drag on to long,she might lose interest. She seems interested though, so i say go for it man.