Nice stuff, watch the placement of the hips though, especially the first woman with the sword, her loincloth is a bit low and the legs are pushed forward a bit to much. The color sketch is a bit muddy and undefined and the skin tones are a bit bland, don't be afraid to mix in some more colors to get some contrast :]
Wow lots of improvement just looking from the top of this page to what you've done recently. Your line quality has really improved. Drawing from life has really helped your rendering also. Keep it up man, very inspiring.
I agree your line quality has definatly improved. Perhaps consider drawing with ballpoint pen or a medium that doesn't allow you to heavy/beef up your lines as much as pencil does. I think this might help you increase your line quality even further, maybe ask around cause I could be wrong.
But I just got to say your work definaltely has some amazing potential especially in the female department. Chuck a female into the shirt on this page and youll have no complaints from me (from an artistic point of view of course).
Keep the design simple for the magazine cover. Chilijapones and myself have to do this stuff all of the time for the company we work for. Go for a good graphic composition that would draw your eye to it from across the room. Then let the viewer enjoy the details after that. Keep posting!