Ask people where they got tattooed, this is especially helpful if you really like the work you see.
At the tattoo shops ask to see photographs of the artist's work, most often, the pictures will have been taken right after the work was completed, so redness and swelling are common.
Look for clean and smooth lines you don't want broken and jagged lines or lines that don't meet up. Check to see if the coloring is solid or uneven or if it is in the lines.
Check to see if the artist does the style for tattoo you are looking for.
Take time to check out a few artists and shops, this will ensure that you are happy with the results of your new tattoo.
Remember price shouldn't matter. You aren't going to find a good tattoo artist that works cheaply, a good tattoo artist knows there good and knows there worth the extra money. Besides, there is alot more that goes into tattooing than what you see and it is harder than it looks.
Also you should consider the following for disease control.
Make sure the front shop is neat and clean, this is usually a pretty good indication of how clean the rest of the shop is.
Ask questions about the shops safety procedures. Example: "What is your shop doing to ensure my health and well-being?" The personnel should be more than willing and able to answer you questions.
All equipment should be single service, this means that each needle and tube set is individually packaged, dated, sealed and autoclaved. The artist should open a fresh set of needles and tubes in front of you and any ointments, pigments, needles, gloves, razors, plastic trays or containers used in applying your new tattoo should be discarded after use. After the tattoo application the artist will disinfect the work area to kill any surface bacteria or viruses.
The artist should be wearing gloves at all times and if broke they should change their gloves immediately. This protects both you and the artist from any bloodborne pathogens that may be present.
An autoclave is the only acceptable means of equipment sterilization in the tattoo shop. It is a machine that uses a combination of heat, steam and pressure to kill all microorganisms known to man. If the shop does not use an autoclave, do not get tattooed there.
Hopefully with these tips you'll find a tattoo shop that can do the type of tattoo you want and have it come out the way you want it. Good Luck!