Wow, your stuff is defenitely better than i can do!
Something about the skin tones look off to me. Try to find that "zing" that brings life to the skin tones. Remember that there are certain "hot" spots and "cool" spots on the body that flux in hue. Primarily the knees, breasts, groin, and buttocks are "warmer" areas where as the lower leg, obliques, back of the neck, and arms are "cooler"
Anyways, i hope that is a relevant tip.
Keep being awesome.