Hey this turned out pretty well! Nice colors on the shirt. The one thing that’s really bothering me is the color of the black tabs on the guitar (don’t know what they’re called) in relation to the background. It makes it looks like he has a really thin neck. Careful with how sharp you make the edges though, some edges should be softer when they are further back. In this picture I would make from sharpest to least: the neck/head of the guitar, the hand holding the guitar, the face, body, then the strumming hand. I did a quick mod with the blur tool just to illustrate this. Hope you don’t mind
http://img404.imageshack.us/img404/3010/blandwolf1ux6.th.jpg