oh my.. this really need some TLC... author..when using so many different images..you really need to get all of their light sources going in the right direction.. at the moment, all the shadows are every which way but loose.. when masking out images its good to place them all in a clear layer and move them around until you line up all the shadows.. then move them into the project.. your composition is solid..now the work to balance and add shadow begins..good luck... I'm sure more peeps will be along to help you along..

some perspective problems exists.

not very well blended but i like it

I have made some improvments, and added a truck.