Please avoid the barb wire and tribal ink, it hasn't been cool since the 80's.
If you have a friend that's somewhat of an artist, ask them. Use random ideas and mix them together, usually results in something unique that isn't without meaning. A lot of people get tattoos to remember things or to express certain views. That or just go to a local tattoo artist with credibility and ask them to come up with something. Just have a vague idea, and they'll fill in the rest.