Select the style of cross you want to get tattooed. With Christian-inspired crosses alone there are many styles, including the Latin cross, the Cross of Triumph and the Russian Orthodox Cross, as well as the Crucifix. Each style has different meanings, as well as different filigrees and designs, that you should consider when creating your tattoo.
Browse cross designs. Looking through art books at the library should uncover various crosses that could be incorporated into a tattoo. There are also many websites that offer help in creating your own tattoo or provide inspiration for it. For example, Tattoo Design showcases 10,000 tattoo ideas. It even features software to "mash" your favorite designs together into one piece of art.
Present your tattoo artist with the ideas you've come up with for your tattoo. If you're artistic, you can sketch out the cross you desire on a piece of paper. If not, bring examples of crosses that you like and point out the features of each one you want incorporated into your tattoo. A good tattoo artist should work with you to create the perfect cross you've envisioned.