Re: Omg a sig :O
Do something with the stock image. It looks like an afterthought almost. It's in a good position, but it just looks like you took any picture you wanted and just slapped it on top.
If you look at the others on here, the ones that recently have been whoring sprites, you'll notice they use the background to convey the motion of the stock image a lot, it works well when the stock flows nicely with the background. If you can work out that aspect, letting the stock flow to the rest, I'd imagine your works will come out looking better.
Most of these things aren't just "do this, put this number in, etc.". The good things require the right eye for the matter. You have to see what will work, how it will, and what needs to be done. Then the effects you learn in the tutorials come into play in order to accomplish the look you envisioned.
Shit I wrote a lot.