Some advice: you need to put yourself out there, you need to take risks. It's very important that you not let her forget about you. Always talk to her, listen to her, engage her. Now, this is the hard part. There's a hidden line you need to be aware of, and avoid crossing. Finding it isn't easy, and every girl hides hers in a different place between you. You can't become irritating, you can't make her feel uncomfortable. Once you cross that line, you can't try to come back from it without making the situation worse. You have to know when you've blown it and when to let go. Charming a girl is all about maintaining this very delicate balance between being persistent, and coming off as a creep. Whatever boundaries she sets, spoken or otherwise, you fucking respect them.
Just seek to become her friend, and if she wants something more, go for that, too. If not, hey, you made a new friend. Don't try to date someone you couldn't see yourself being good friends with.