you can tell from the sonic pic that your good at art you just need to understand how graffiti works. why that extension works or doesnt work etc.
res - the only art i do is graff,i barely do characters..i feel u tho zewl - looks good,stretch the top part of the z more to the left and thats a good simple lost - if ur gonna post pictures do it in one post..and read everything , http://www.bombingscience.com/graffitiforum/showthread.php?t=2185
Holy jizz thats ridiculous. Do fucking keyboard letters. Ditch that first pic entirely. Pretend it didn't happen. For the second one try to round everything out so u dont have weird sharp edges. That K is not working, ditch that, and the shadow is way off.
If you think you need to tell us what it says, then you are doing it wrong, and need to start doing it right.