Let me tell you what I'm glad I did, first:
I'm glad I waited til I was older. By age 21, I could easily tolerate the pain, afford it, and not make a stupid choice in design.
I am glad I did the "pick and wait" method. The first design I picked I ended up not liking, good thing it wasn't too late. Be sure you know for sure what you want, otherwise you will be very unhappy later, with a very expensive mistake.
Starting with something simple is a good move. It eases you into the feeling and idea of having a tattoo. Then you can always add on, touch up later.
Checking out lots of stores. Don't just settle with a store just because it can ink you. Look for a place with work you really admire. Make sure their space is clean and that they take good care of their instruments and customers.
If you talk to people with tattoos already, ask about their experiences. Why did they pick that design? Did anything go wrong with the tattooing? Would you go back there? etc. People with tattoos love to talk about them, and will be very open if they are happy or displeased with their artwork.
Now, what I regret:
The exact postion on my shoulder. My bras and tank top straps always hide my little guy, and you only see just his head or just his tail. I should have moved him over one way or the other. But its not a terrible mistake, I just have to buy new halter tops to show him completely. I thought it was the perfect spot, I just over looked one little problem.
Hmm, that actually seems to be it. I am very happy with my tattoo. I love to show it off and have people notice it. He turned out much better than I thought and is a great addition to my life. What better way can I confess my love for dragons!