Your backgrounds are usually nice but the text and render and lighting suck in most of your sigs. Try a grew soft brush on linear dodge and lower the opacity and don't stretch the renders, maybe fix them up in Topaz or Redynamix.
As for the text just use a simple font that looks nice and use color! Mess around with the blending modes, blur part of it, sharpen, clipping mask, etc.. whatever looks good.
and try not to whip out sigs all the time, take your time and be proud of what you make no matter what anyone else says as long as you like it thats what counts.