I want to tell a girl a like her... I need some advice on how to approach it

Background: This girl and I have been sitting at lunch together for about 1 school year. I usually never see her outside of school. Me and her have a lot in common (we watch the same TV shows, have the same hobbies). I haven't made any moves on her, and I have no indication that I'm in the friend zone, or if she likes me romantically. Any advice on how to proceed from here?