Crap guise cut some slack. Eventhoughyounevercutmeanyonmyfirsttime
Looks like all beginner's turnout: A render slapped onto a background. Do what these peeps suggested and scrap it completely. Bu try doing something more reasonable. I'm not saying go explore tuts (because they are ALL just horrible) but you might want to look at some just to get around the GIMP settings. Cause real GFXers make original shit. I didn't figure that out until like 6 months into doing this thing. But yeah, grab some techniques from tuts and experiment on your own to develop your own style.
So, for CnC on the actual tag. What you want to do is integrate the render into the tag by adding some depth. You can do that so many ways it's retarded. So you might want to look into that. Also, work on coloring. If a combination of colors sounds shitty, it most likely is (i.e. Green and Brown). As for this tag, it looks like swamp-y colors mixed with puke. Finally, never do that gray shit you did to the render ever again. I can see what you were going for, but unless you're paintedape, do mess with the actual render...like at all. And I'm guessing this tag took like 10-20 minutes? If that? Good tags actually take time to develop so don't rush when making one.
Hope this helps.