find some abstract brush packs or grunge ones..whichever you prefer and brush up that background..its to plain!..and try multicoloring..its always good to learn that early..heres a link to it..Angry Johnny's mutlicoloring tutorial for you! You should also try out Juicy's render blender tutorial under Other Tutorials..should be one of the first 3 there..

anyways about the sig..way to dark..after you brush and color it more..try adding some brightness/contrast to it..but not TOO much at all..otherwise it won't look that good..for text I always go to DaFont grab some there and try em out..and as for coloring..just basically experiment with em..anyways..good luck man! Hope that helps ya

Ps: a border would look good on it and maybe a smaller size.. :P