How do I talk to a girl?

There is a girl that I am interested in, and I need some advice on how to talk to her. Every weekend my family and I go to a pizza place. There is a cute waitress that works there. She is only about a year older than me. I do not live in the same town. We have been going there for months, and I want to know how to start a conversation with her, and eventually find out if she might be interested in me.