You have part of what makes a signature down, that being the rule of thirds.. or partially. There's a lot of space where there's nothing really to look at, and it makes the signature kind of boring. The picture you used for the bottom corner needs to blend more into the signature, and should be devoid of white around the edges unless that's the stye you're looking for. You also need to incorporate a little more color theory into the art. Blue and yellow work together, yes, but the complimentary color to blue is orange, and would work much better with the character given his affinity to fire. It seems like it's lacking something. For a first try, it's not too bad. But work on it.
It's not bad for a first try, but what do I know, I can't make signature banners for junk. Dx
I agree with Zr388 though and pretty much everyone here, 4/10.
It's your first signature, so there isn't really much to expect. I see the obligatory GIMP light ball brush, though. Cool story. Check the interwebs for tutorials and things for GIMP to amp up your skills. Should help a bit.
Good,Good. 4/10. Have you followed some of the tips I gave you on the IRC? But you are good for a beginner,it's just like my very first signature.Now look at the sigs I make now.