Try downloading some nice grunge brushes to make a good background. Also try getting your renders from psd sites as they will look a lot better than ones you cut yourself. These can be found in the resources section.
yea, I bet you could do better, The BG is pretty bad, the pic is blurry, it looks like you copy pasted it on there then stoped there. But The Text is ok, not the greatest but meh. All you can do is keep practicing and im sure you will improve.