Some of them are good, especially the MPGH one. You have to learn the flow of the colors a little better, because some of those color match-ups are pretty bad. Using the founding principles and elements of design can make any work look professional- even graffiti. It's an art like any other, so take some time to sit down and experiment with color flow and line weight.
"Drive it like you stole it. Wait a second. Did you steal it?"