Come up with your graffiti artist pseudonym by thinking of monikers, nicknames and shortened versions of your name that you might be able to use. Most graffiti tags are short and simple because it makes them easier to apply with spray paint.
Practice writing out the pseudonym in different kinds of graffiti lettering. You should choose a lettering style that fits you and that you are comfortable with. Some popular lettering styles include bubbling, rounder letters along with rough and sharp lettering, which is typically found in tags in grittier, urban areas, whereas bubbly lettering is commonly used in more gentrified graffiti.
Continue to practice writing down the tag using your pencil and paper, erasing areas of the tag as you deem necessary. It's important to practice the tag on paper until you've achieved one with good, equal proportions.
Take a copy of your completed graffiti tag with you to a wall you can practice on using spray paint. Slowly and lightly apply spray paint to the wall, holding the can a few inches away from the wall, following the drawn-out tag as best that you can. Continue to practice until you're able to recreate the tag with spray paint.