Best way to get to know a girl ...?

I have a crush on this girl who works down at the coffee shop nearest me. We don't have much of a relationship aside from the typical customer/employee one, but there seems to be a certain rapport between us. She has this luminous presence, and I find myself absolutely drawn to her, but I have no idea how to talk to her. The place is usually dead in the evening hours, so I plan on going there sometime soon in the evening to attempt to talk to her. I have no clue what I'm going to say though...