Tomte: One word proportions, don't put any clothes on him until you got the proportions right. However the arm was bloked out quite well, maybe pull in the tricep a bit.

http://i.imgur.com/4P4x85H.gif

Just have this close at hand when you'll be drawing your next drawing and it will look much better.
http://www.foundation3d.com/uploads/instruction/2008/10/17-10-622362.jpg