Write a list of names that reflect your personality. Ideally, stick with one word and no more than eight letters. Make the list longer than it needs to be and brainstorm with friends if you're having trouble coming up with something you like.
Choose your five favorite names from the list. Select names that have the appropriate degree of swagger and bravado while also using a variety of letters. A longer name grants you more artistic possibilities than would be available in a three-letter tag that has two repeating letters, like ALL.
Sketch out a graphic, graffiti-style tag for each of the names. Draw them each on a separate piece of paper, keeping in mind that you will eventually be drawing the name with a marker or a can of spray paint.
Choose the tag that you like the best. The perfect tag has visual style, emotional impact, a variety of letters and a bit of bluster to it. You want something that sticks out but isn't too obnoxious. Again, if you're having trouble, feel free to ask your friends to help you decide.