Just be yourself. There must be something about her beyond being a girl that you find interesting. Don’t flirt, just be friendly, and if there’s a common bond it might go somewhere. Or not. But if you don’t do something and she doesn’t, then neither will know. This is coming from a heavy introvert who avoids people in general. It’s hard to get past that first step, but once you do (and you don’t force something to happen) it gets easier, and the relationship usually builds from the point where both are more relaxed and… being themselves.