The main render is way too contrasted and looks super low quality. I'd try using some nice background stocks instead of a duplicate render as the BG.
Fuck man, the GFX game has changed. If this was a few years ago I'd link you to some stock packs and PSD packs to show you some of the basics. There's no room for improvement these days for the new comers.
Just keep fucking around in Ps man and you'll learn new things. Gradients and gradient maps are your friend for blending.
Lots of multiply, screen, lighten and darken layer modes too.
For what it's worth, I like your sig now. Looks almost antique-ish. Just wish the saturation was toned down a bit.