I like how you do your lines. It is rather powerful and has great variation (which makes it interesting, I find).
However, there are a few anatomical issues with him. His biceps are two different sizes. I think the one on the right (his left) is the better of the two. Also, I think the area from his neck to his shoulders wouldn't be that shallow. There would be more mass there (especially since he is a muscular man).
I am a bit confused by his shirt. Does he have on an undershirt and a vest? If so, then there should be more definition of this (more bulk to the edges). And, this is a very small thing and probably just me, but the loose bit on the belt seems to be at an angle that isn't quite right. It seems to be close, but just a little off, and it seems to be getting larger at the end (a bit more than perspective would allow).
I really love how you've draped things! The necklaces and his hair look great! His expression is also great!
Overall, nice job. I look forward to seeing how you improve!