Drawing Like an Animator

Ever since I was a kid, I always wanted to draw like an animator. I never liked the "stiff" looking poses I saw in comic books and always wondered how animators got that "je ne sais quoi" that made their work really leap off of the page and seem as though it were actually alive.
 It turns out, part of what I've been searching for this whole time is volume, weight, and structure. Its that emphasis and understanding of the underlying structure that really sells a drawing and makes it seem real. Where others might be more concerned with the colors and details, animators are trying to understand volume, weight, structure and the mechanics of how things turn in space.
I'm striving to get more of that in my own personal work. These are some (rough) development sketches for a series I would like to create.