J.B.
Bring cash for the tip, they won't take a cc for that. Any shade of pink is usually good - you can go a little bolder/brighter/darker on your toes than you would on your hands. I normally go with something fuschia-y but there are lots of fun colors, pick your fave!
The first thing they'll say to you is some version of "pick you color" which where I go sounds something like "pee-kah-laaaaaahhhh?" so I didn't quite know what the technician was saying the first time. If there are various options for the pedicure you'll have to say which pedi you're getting (regular vs. hot stone vs. paraffin, etc.). Beyond that, you just sit in the chair, relax and let the technician do her thing. The chairs usually have a massager built in and they usually massage your calves as part of the service.
Remember to bring open-toed shoes to go home in and have fun!