I had a couple of artists in mind. One was a shop in my home town which was good, the shop was clean, no-one had any horror stories, but they were busy and every time i went in, I ended up speaking to a difference artist and having to explain the design idea all over again. It got frustrating ...
the guy who did my tattoo was a friend of a friend (not always a good idea, and i had my doubts). He was recommended over another friend-of-a-friend and there wasn't really a "portfolio" as such. There was the friend in common rolling up his trouser legs and saying "This was Vince, when he started out. That one was as well, but he's since done a cover up. This was [another guy], this was vince about three years ago, and this is a current free-hand one". That convinced me And he's the one that his family go to and everything.
Aside from being ribbed mercilessily because I was nervous, he was perfect.

I always suggest that you find the portfolio with the art that most suits your ideas, then have a consultation with that artist. If you feel good about it after that, you've found your artist...pay what they ask.

If you don't feel good about it after your consultation, start over again.

^ what he said x10000

ditto.

my artist was the only one in miles who had a great portfolio, who was clean, had a tonne of awards for his work and tended to not like doing the stenciled tats that everyone gets, which i liked. pretty easy choice for me. if i were surrounded by great artists id be in hell choosing one lol