I like your trees - the leaves could use more defining but that looks like a solid start. Anyway, your light sources still aren't agreeing. For example look at the rock on the right; to be lit like that the light would have to be coming from above it and toward (or behind) the camera. Now look at the shadows the trees are casting. They're coming toward the camera, so the light would have to be further off, behind them. Your cart racing guy's shadow needs desaturating I think... though looking at that part, the light sources are confused there too. The sparks (I'm assuming those are sparks) coming off the cart would be a small light source in themselves, which would mean that the shadow of the cart/racer would be weaker around them if not gone altogether.
As always, hope it helps.
