Nice job on the sig! I love that you're trying out sigs and you're getting better at em!
Alright, lemme start with the CnC (it may be a little shaky because I'm feeling a bit groggy >_<)
Alright, so the first thing I've noticed i that the canvas size is way too large for this render's size.
The height dimensions are okay but the width is too much. Cutting down the size of this tag will create a better visual feel and will make the tag look less empty because there's not much going on apart from some fractalic art and some text.
Also, the positioning of the render and the text is off. A render of this stature would be best suited directly in the middle of the canvas, thus bypassing the rule of thirds grid positioning.
You also need to start working with a few more adjustment layers (dont be afraid to play around with more filters and effects). If you have PS Cs6, try using the color lookup filter, it works wonders
The lighting is a bit off, or rather its very poor. Browse around for some tuts on proper lighting techniques and stuff. You could also try the simple lighting trick of making a new layer, filling it with black, setting it on linear dodge and then brush with a suitable softbrush size with the color of light that you wanna use to make the lighting "pop".
Dodging and burning should be used as well.
Also, depth is lacking here. Try the simple process of blurring the applied image and erasing the focal points around the tag.
Now for the text; I already spoke of the positioning of it already. So now I'm gonna talk about the actual look.
So you need to browse around for better fonts. Try using Bebas neue, Impact or stuff like that for the main text, and then some curly fonts, like "before the rain" and stuff like that (there are tons of them out there) (or you can choose fonts that match the theme of your tag)
I'd suggest you get some new gradient swatches, check around on DA and you'll find tons of them.
Also, find a better
tiny text brush, the one that you've used looks like you tried making tiny text yourself by typing small scale fonts and positioning them to fit the text(it doesnt fit >_<)
Anyways, good attempt!

KIU!