Tagging, the most basic form of graffiti art, is basically a stylized depiction of the graffiti artist's name, usually incorporating only one color. The tag can be by itself or as a signature alongside a more elaborate work of art. During the style wars of the 1970s, graffiti artists would try to outdo each other's tags, using more and more elaborate details, bold colors and larger designs. Putting one's tag over another artist's tag or graffiti art is considered a sign of disrespect.
A throw-up, while more elaborate than just a basic tag, is still pretty primitive and is usually executed quickly, as the name would imply. Most throw-ups incorporate three colors and include bubble letters, sometimes with the letters outlined in a different color. When a graffiti artist goes bombing, or covers an area with large amounts of graffiti, he usually works with tags or throw-ups.
Another quick method for executing graffiti art is to use a stencil. This way the artist can create an elaborate design beforehand that only requires placing it against the wall and spray painting around it. The famous graffiti artist Banksy is known for this method and helped bring the style into popularity.
Wild style is an elaborate, and sometimes difficult to decipher, form of graffiti art. Created with multiple colors, the wild style sometimes features a 3D effect and incorporates graphics like curves, arrows and spikes. This more sophisticated form of graffiti was first popularized in New York City.
A sticker is an adhesive-backed form of graffiti art. Also known as slaps, some artists like this method because they can take their time working on their art in private, then spend less time at the graffiti site itself. This type of graffiti can be as simple as a "My Name Is ___" sticker, or can be an original, fully realized work of art.