My word of advice would be to just be confident and be yourself. You need to be confident, but don't scare here away. Give her a few compliments, and just treat her nicely. Don't use those corny pick-up lines you read on the internet... you'll feel like an idiot. Don't move too fast, move slowly, and if you see that she may like you too, then maybe move a little faster. Just be confident and be yourself, and don't pretend to be something that you're not. If you take it slow in the beginning, it'll work out a lot better for the friendship if she doesn't like you like that. If you move too fast, it'll destroy the friendship.