In my opinion, a tattoo should be an indivual's design/idea. It should be something that for you resembles something special, unique, etc. Not something you see on every other person's body. Sort of like girls who get lower back tattoos of butterflies and other nonsense that you see on every other girl walking around on a beach. Nowadays it seems everyone gets tattoos because everyone else has one. It's almost as the newest thing to have in order to fit in.
Think of things that you'd like to have on your body. Something that reminds you of something or somehow says something about you or a hobby you have. Maybe something that can be associated with a nickname you have. Something special or unique about you that can be represented as art on your wrist. Or if you have an idea go into a tattoo shop and have an artist draw something for you. You can have them alter the drawing until you are satisfied with what they draw.