are you working on this off the top of your head? I'd advise you to just do a few minutes research, on google or something, there are more reference pictures and sites about how to go about the human body than you can shake a stick at. Atm it honestly doesn't make a whole lotta sense, you need to know the path you want to follow before someone can help you on your way.
You may not want to be 100% anatomically correct but knowing how to go about drawing certain parts of the body and knowing how to go about constructing it will help you in the long run.
This is a quick image search for comparisant, but I'd strongly suggest you research further.
http://turboatomic.com/media/1/20060803-Full_body_v5_small.jpgThe amount of views doesn't mean a thing, I could get hundreds but it wont mean people are just looking at my thread and leaving. Not everyone on this forum will know exactly what to say, because the human body is a complicated thing, I sure don't know how to draw it perfectly I'd be in the same boat as you, I just know from thread after thread on many forums that taking the time to understand your subject material is the way to go, lets say, look before you leap. Also I think there may be a lot of lurkers about too.
Aswell I think having a bit more contrast with your palette will help you too, the shading is there, but without a lot of contrast between the shades it will just look a bit flat.