Let her see you as a friendly nice guy and be the best you, you can be. Be available and talk to her. Tell her that you like her. Ask her if she feels the same. If she says she likes you, ask her if she would like to be her girlfriend. If she does not like you, don't ask about being the girlfriend.
You got to take a change for rejection to get the girl. Don't let the chance of having a good thing, stop you from trying.