phoenix is right.
and never forget, blur and burn tool are your biggest friends.
+one of my fav. tricks: if you dont like the outcome at all, but still have some nice parts in the sig itself, just do what i did with yours:
burn tool everything around your focal point.(you should have your focal on a black or white bg now)
then use the tips phoenix gave you. lighten the hotspots, add gradients, and a nice font. and remember to take a look at image>adjustments(should be the right name. i got the ger. version, correct me if im wrong) there are a lot of options to change contrast+lighting. this can fix some problems with your lighting easily.
its no big deal but when you do it right the outcome looks pretty cool imo.
->did it on your sig:
(look at my current sig. its one of my best, about2 years old tho
i used the same technique on it,too.just with a little bit more effort heh :P )