Study the signatures of other artists. Look through picture books hosting the works of famous graffiti artists. Check out museum exhibits, such as the one held at the Brooklyn Museum called "Graffiti Basics." Note what you like or dislike about each artist's tagging style.
Print your name on a piece of paper. Without over-thinking it just yet, see what you naturally come up with. Tweak the aspects you dislike. Keep the aspects you do like.
Vary the shape of your letters. Block letters, bubble letters, and messy, cursive lines are popular styles in graffiti signatures. Try each of these to see which looks best with the letters of your name. Feel out which is most natural to write for your particular writing style.
Slowly and carefully write out each letter once you've decided on a basic style. Your signature won't always be this painstaking to write out. For now, you are trying to get the letters perfect so that you can memorize the look and feel of writing them.
Add details. Put stylized dots and lines through certain letters that require them, such as "A" and "i." Incorporate shapes, figures, shadows or 3-D effects by varying your line thickness and shading add-on areas in a darker color. Color in your letters to make them brighter and color-coordinated.