Try checking out paintings as well - there's also a system called "Contra-Posto" (Counter Poise) that painters and sculptors uses for creating body poses. Sometimes it's easier to see how other artists achieve a "natural" look, because usually they "cheat" in some way - add exaggerations in areas of weight etc - the "Lead Hands" approach is most noticeable - the figure looks like their hands are really heavy, creating an interesting slope to shoulders and curve to the limbs etc...