Another late joiner here (!)
The three things I will definitely keep in mind for next time are to start with an even bigger canvas, use the brush instead of the pencil, and just shrink it down to size later. I stuck with pencil the whole way through this sketch, and probably paid for it.
Ignoring the hideous head (sly bald chicken?), what displeased me the most was the bareness of the torso in general. I, with pencil, could not produce anything that did not look like a mortal wound on the abdomen, so I gave up on trying to do away with the blankness.
I also failed to give my sketch the emaciated, and therefore aggressive, look that I wanted; it came out plumper, not to mention much flatter, than I would have liked.
Final note: That is not a beard/goatee. That is lower-jaw-mold.