Safety should be your first concern when you're getting a tattoo. Make sure your tattoo artist is well-trained and works for a licensed tattoo shop. Also look at examples of your tattoo artist's work to make sure he knows what he's doing. Talk to other people who have been worked on by your artist about their experience.
Tattoo shops are potential breeding grounds for disease. The tattooing needle pierces the first dozen or so levels of skin, causing light bleeding. If the tattoo artist reuses needles, this practice can pass along diseases such as HIV and hepatitis. Due to these risks, it is critical you get your tattoo from a licensed tattoo shop. Within the U.S., licensing laws vary from state to state. The shop should have its paperwork displayed prominently.
In addition to using brand new needles for each tattoo, your tattoo artist should also use fresh ink. Tattoo ink expires, so make sure the ink to be used on you has not expired. No tattoo ink has been approved by the Federal Drug Administration. Some inks have heavy metals in them that are not safe for use in humans. Look at the ingredient list of the ink to be used on your skin.