You ponder for a bit, text her when she goes on a night out and then she rings you and refers to you to her friends as "this cute guy I met", and then next time you're face to face you bring it up, talk over the situation, "do the bad thing"...
It does happen.
Whether or not you're the kind of person who thinks nothing ever works out for them, or that luck is purely an antagonistic force that is hellbent on keeping you single, you just gotta keep talking to people, keep meeting them and eventually there'll be someone who it seems with no effort on your part you ended up with because things just... worked.
All this "tell them you like them, will they like you back?" stuff you had to go through at school just adds unnecessary pressure that only ever works against you. If you both like each other, chances are you won't need to say it in an awkward confession.