I have to agree with most people here and say that the first picture has some serious clipping issues. It can be hard to get rid of all those nasty edges, but it can be done.
The first picture is a little dark also, with the right side of the guitarist not really fitting in with the scene, should be darker as the background is the only light source.
Other than that its good. The light beams are nice, but could do with blurring and shadowing out closer to the ends, at the moment they appear to stop in their tracks!
As for the second image, I like it. I think you've done the swirly bits around the guitar incredibly well. Not an easy thing to pull off but you've done it nicely. Again as in the first picture, not a big fan of the overall darkness. The backgound could do with some work as well... Not sure what you could do instead of the current background, but its worth playing around with some ideas until you come up with something more "eye catching".
Keep it up! Some good work.
