Hmm i see some new faces. ^^
Ok, first of all, put a border around it, a very basic thing, but quite needed on almost any sigs.
Don't know how?
Make new layer, hit ctrl+a, go to edit > stroke, i prefer a black 1 px, and put it on
inside.
Next, try to get more colours in it.
A good way to do that is to do some gradiant maps.
On your layer screen, there is a little cirle black/white ish thing on the bottom, next to the delete button, press that and choose gradiant/gradiant map.
Then choose some fitting colours and play with the layer mode.
Oh and you can do so much things with text, i think i never made a good fitting text, but play around with it.
Also make the sig background have more action in it, use image > apply image, and use some filters.
Or you could just do some tutorials.
Good luck.