ive been told that my choosing of colors for my backgrounds in my sigs doesn't go ell with the pics...

what kind of tips/advice could u guys give for selecting colors and such

You could take colors off the render/focal and use those
Or look up Color Theory and see what colors look good together

http://senthrax.deviantart.com/art/Full-Signature-Tutorial-55042010


Read the entire guide, and understand the meaning with blending, focal points, colors, flow etc etc.

All you need to know, you will find in the guide i linked.

http://forums.d2jsp.org/topic.php?t=69800352&f=246

don't be afraid to use adjustment layers to change colors as you go