Concerning the, "Da-Bomb-Erz" image, it looks pretty good. The basic concept works, though it's suffering quite a bit technically.
Graphics for teams and such really need to be flashy and eye-catching. You want a lot of motion going on and some interesting colors.
The biggest flaw with this is the white background. White sucks the contrast out of everything and should pretty much never be used for a background, unless still work in progress (but even then, as soon as you start adding colors, the first step should be to get rid of all the white).
The second flaw is that there's nothing really going on. It seems very static and flat with little motion beyond the burning fuse.
And the last is a bit over-saturated text with no, "pizazz" to it.
So overall the flashyness and, "pop" need to be bumped up quite a bit. Here's a quick remake to show the kind of stuff I'm talking about: [Link]
The colors you choose would depend greatly on what you're trying to convey. Every color has a meaning; fast food restaurants use lots of red and yellow because they convey urgency and intensity, causing customers to get in and out much quicker. Whereas blues and purples are very calm, relaxing colors that denote peace and relaxation. Do some study on colors and find which ones would best work for your image.
Keep at it! :D