Tattoo Placement - Placement is a huge factor in the attractiveness of body art. A well done tattoo that is the right size will still look terrible if its placed on the wrong part of the body. A small design that looks sexy on the pantie line may look completely ridiculous on the lower back. Also bad placement makes cover up tattooing much more difficult.
Tattoo Subject - The subject matter of the design is an important factor in creating a sexy tattoo. From roses to skulls many subjects can be converted into attractive tattoo designs. The key is picking an image that is universally thought of as attractive. Many designs begin as shocking but add sexy elements i.e. a skull with a pink bow on it's head. While many subjects can be used, one of the biggest factors in a sexy tattoo is not to get objectionable imagery.
Tattoo Quality - Maybe the most important quality in a sexy tattoo is quality of the work done. If the size, placement and subject matter of the design are all perfect but the artist is not qualified you will never have a sexy tattoo. The smoothness of the shading the clarity of the color palette and the crispness of the lines are all the signs of a good tattoo artist. So the first step in getting a sexy tattoo is taking the time to seek out a well versed tattoo artist.