He's a well-fed bloke, isn't he?
Seems to be a pretty damn fine first if you ask me. His pose is what we drawing types call a 'stiff' however. If you're looking for more help in anatomy I would recommend Google images for posing people, general anatomy and bone structure. Just a little of an inside-look and reference material can drastically improve structural work. Furthermore, I should add that the best poses always have a 'running curve' through their entirety. The human body is very flexible with many curves.
I do like the intimidating slant of his stance, mind you, especially if he's in front of a smaller figure.
The clothing lacks some obvious details, but otherwise you do have flow and weight down properly, and the lack of details is easily justified by the setting.