I agree with fire on some points here are my view:

1. the render seems squashed remember to hold down shift while resize.
2. Depht there a not much depht in there try to add that,
3. colors are very monotone there are only one color in there almost.

bit i disagree with fire on finding a style and then only work on that, then you will end up being good at just one thing in stead of many -,d