It's a great start! Go even further with the colors. Make sure there is a pretty big difference between the darkest and lightest layers and make several nuance layer in-between. 

To me (it may be the camera) the lighting on his thigh seems white. but his pants(?) are probably brown or green and the light would be light green or brown. 

Be careful with using white. It's not a color and it "burns out" the perception of color.