Decide on the overall crest design. Look up your family's surname and find out what it means. Create a design that captures the meaning of your name symbolically. Consider using a free website such as All Family Crests to look up your last name (see Resources).
Learn what the various elements are by looking at a design element breakdown of the family crest (see Resources). It's a good idea to keep it handy as you draw your family crest. Be as accurate as possible, since the tattoo will be permanent.
Sketch your crest. Make the sketch larger than the size you want the final tattoo to be. The sketch is what your tattoo artist will work from, and the easier it is for him to see the sketch, the closer he can get to your design. If you aren't an artist, try tracing the elements from other sources. Try to keep your design majestic, using medieval elements such as knights, swords and spears. The crest should have a regal, historic overall look.
Use color pencils to finish your design. Add color to the elements of your crest and use a lead pencil to shade in any areas where you want the tattoo to appear three-dimensional. Match your sketch as closely to the finished tattoo as you can, both in shape and color.