Signature needs loads of work.
Considering it's your first work, I'll give some tips, like other MPGHieans did with me:
1. Get resources (fonts, brushes, effects like C4Ds, Fractals,etc...) and use them.
Try to get a premade signature and learn how he used each layer and how to aply C4D (google all resources, most reliable site for beginning would be DeviantArt)
2.Get to experiment with the resources, making loads of sigs will eventually make you focus on what you want and doing it faster.
3.Watch tutorials, a boring step but can be very important.
I dislike GIMP but there are resources out there, and people who can help you better than me. I'm more of a photoshop guy.
Formerly known as gamer4evere
MPGH GAMING NIGHT 08/03/2015 - Town of Salem