Haha I agree with you on that, I'll always remember my first signature
I cut out the render and everything
Seems as if you put more time and thought into the second one, good job there's already a lot of improvement there. I recommend switching over to Photoshop though, It will pay off in the long run when your graphics start getting more advance. Gimp is more of a beginner program, which is good for now but once you start trying to achieve harder effects, you'll find them much easier to do in Photoshop. Sometimes applying effects in GIMP takes a little more time, as there is not so much automation available but if you know what you're doing, there's not much that can't be achieved in GIMP.
As always practice makes perfect, you'll only improve over time so don't give up. Watch some tutorials to help you get a better understanding of the program and what some of the tools do. PM me if you ever need help with your graphics or just have questions, keep it up mate