Long story short, I've been building up my confidence approaching random girls around campus and having short conversations with them (EX: Directions to a building I already know, advice about a professor, what your major is, etc. etc.). And they've all gone relatively well, but the issue is I don't know how to keep the conversation going past the initial exchange.

Usually with a girl, I just read her body language and exit gracefully because she's heading somewhere and just wanted to be courteous but with some girls I genuinely felt like we could've had more of a dialogue/maybe swap numbers but I got a bit tongue-twisted and just ran out of stuff to say.

So basically, how do you keep the conversation going and build a rapport for someone you just met for the first time? What are some go-to topics that you pull out to renew interest if/when it starts to get awkward? Thanks! :)