Have you observed the graffiti downtown? If you haven't, then take a peek this weekend and look closely to find out what I mean about self-expression. After checking it out, you'll see that graffiti is not pure vandalism after all. In fact there are organizations or groups of people who became well-known because of graffiti and are now paid well to create it.
One such group is the TATS CRU in New York who are paid to paint on street walls, subways and streets. Tats Cru claim to be "The mural kings who have changed public opinion of graffiti as an art form and have taken it to new heights." It is no longer seen as vandalism.
If you want to learn this art form, start the easy way to become a graffiti king. Grab a large piece of paper-preferably plain newsprint which is cheap, use a piece of charcoal or graphite pencil, and start with a few letters all in caps. Keeping it large will help you when you get to that huge wall that looks inviting!
It is best to take a look at some of the graffiti writing on Google images, you'll find a myriad of styles but choose one you like and copy it (for practice only.) You can use markers but using them on newsprint, they tend to bleed too much.
After you've practiced a bit, stand back and view your work. If you see one you really like and think it is great, you're ready to attack the nearest wall!
The practice run is over and you have chosen your own personal style--but wait a bit, isn't is pretty near so many of the other style you've seen? Can you differentiate it as your own? If not, back to the drawing board for a little more practice please.
The bubble-style graffiti is global; you find it on every wall in Africa, America and even Timbuktu. So make yours unique. How? Experiments as these dudes have done in New York-try straight and curved lines instead of all curves-or try dashes. Yeah, you CAN be creative!