To make it easier to criticise, you should put some of them together to make them look like an actual scene.
From what i can see now, the lighting is all of the place. Is the light-source on the left or right, bottom or top? Instead of mirroring them, you should really try and create them individually.
Aside from this, this is a solid base and a few minor improvements can have a massive positive impact.
If you need me to clarify my points, please ask.