Beginning artists often ask me which part of the body I begin drawing first when constructing a character. The generally accepted advice is to decide on where you plan to set the character in perspective, then draw the horizon line, draw the head and then a skeleton.
But I don't draw a character that way - only responsible professionals draw characters that way. I deal in impressions and energy and that is why I draw characters after a theory long-since-learned and long-since-forgotten that I picked up in acting school a million years ago:
Find the body part that most expresses the character (also helps to try and figure out why that body part best expresses the character) and start from there. You'd think it would be the eyes but that's often not the case. If it's a highly confident character, brimming with bravado - I'll have him walk with his belt forward (ahem - doesn't take science to figure out why). If it's a highly excitable extroverted character, I'll start with the hands. If it's a very emotionally repressed minimalistic character, I'll start with the eyebrows (keeping them as straight and disapproving as possible).
As in silent movies, drawn characters often lack the dialogue which literature utilizes to effectively express internal conflict. Locating and exploiting the physical trait that silently expresses personality may be the decisive subtle touch which animates a pencil drawing into a person.