remember that all tattoos spread over time. so even the cleanest crispest art will get soft around the edges after, say, 10 years or so. because of that make sure you don't get your heart set on something ridiculously intricate with tiny detail.
also remember that there's very little regulation over the ingredients in tattoo ink. rather, all tattoo ink is subject to regulation by the FDA, but by and large there's really not much oversight happening in the industry. for that reason make sure you go to a reputable shop. this isn't time to bargain hunt and trade quality or safety for a small discount.
visit a few shops, it's all fine and good to look at the stock art on the wall (most places hang stock art) but what you really want to see is their work binder with photos of actual work done. take your time. sit back and flip through their photos and see if you see a good consistent style. talk to the artist about what you'd like and see how engaged they are in the discussion. definitely leave after that first visit and think it over. if you feel good about what you saw at one of the shops, go back and have the work done. don't feel like you have to get it done the very first day you walk in to talk to them.
lastly, they're artists. if you pick an artist whose work you admire and he/she makes recommendations, listen to their advice. if they say it's too small, it's probably too small. if they suggest changing the angle of the design, consider their suggestion.