Make an appointment to see him or her, and talk about your design and ask them any questions you may have. See if you can get along and make your plans into a beautiful work of art. This is crucial. If the shop looks like an old junkyard, its not likely to be the best place to get tattooed. A tattoo shop must be as clinical as a hospital, there are to many risks involved by ignoring the hygeine.
Sterilization is the key issue in save tattooing.
Don't be satisfied if the tattooists says he is using new needles. So all needles have to be Autoclave sterilized new or used, this is the only way to make sure that they are save. If the Tattooist does not sterilize the tubes it has no use to use sterilized needles. If you don't trust the tattoo shop, ask if you can see their autoclave unit. I wrote this article in the first place for people who don't have any experience with tattoo's, tattooists, or the other important things around this subject.