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In the first image, the man's legs are slightly slanted, along with the trains position themself. I'd recommend you eliminate the part of the building that shows on the top right corner. The hot air balloons remind me of my friend's picture on his hallway wall.. those look ripe with movement.
Second image is just fun to look at.. 2 citizens hanging off a fishing net, garbage net, waste management Tarzan disposal unit?
Although it lacks in definite color, that 3rd one would look sharp on any resturaunt wall.. I like the rain effect and concept. You could brighten the car lights and add some puddles into the street surface.
Hope any comments have helped.
Keep doing you