1. Cleanliness. No matter what, the tattoo studio you are looking for must be clean and tidy. This is the first point, no excuses. Be sure the tattoo artist you are considering follows the main hygienical rules: single-used and sealed needles, tissue paper to cover anything he or she is going to use during the session, disposable gloves. No infections, thanks.
2. Professionalism. Before you decide which artist is going to draw your skin permanently, you should really take some time to talk with them. Go to the shop and expose your idea, what you want and what you expect to get. Ask anything you want to know to feel relaxed and see how the person in front of you answers and reacts: professionalism in dealing with clients makes the difference between a real tattoo artist and someone who just makes tattoos.
3. Social medias. Before you go door by door to any tattoo shop coming through your mind, do an accurate research. Nowadays, social medias are much helpful: you can easily find any tattoo artist you want to know about and see how he or she works.
4. Tattoo artist’s style. Of course they can do many different subjects, probably including the one you want, but tattoo artists usually specialize in one or two styles. So if you want a Japanese dragon be sure to speak to someone who has practice in this field, or your dragon risks to look like a lizard. A “not Japanese” lizard, moreover. Each style has meticulous rules so be sure your tattoo artist knows them!
5. Price. Unfortunately tattoos are usually pretty expensive but if they are well done, it is worth it. Trough social medias you should already have seen the tattoo artists you like the most but, generally, the more competent and famous the tattoo artist is, the more expensive his tattoos will be. Many of them establish a price per hour, whatever the tattoo will be. The best thing you can do is to go to their shop and ask (see point 2).
6. References. Do not listen to urban legends and hearsay stories, but if you personally know someone who got a tattoo from the artist you are considering, just ask them. References can help you understand what you are going through.
7. Please, do not get inked by someone just because you saw him/her on TV. Get solid information. Always.