not bad. if your looking to work on shading, my only advise is to study from life. buy a lamp and some simple shapes or a wooden man, and start making different lighting situations to better understand how shadows work. in this picture, I think heavier blacks and more contrast could help(esspecialy around the face and cloth) to add to the mystique of the character. your defenatley on the right track.
"The only verdict is vengeance; a vendetta, held as a votive, not in vain,
for the value and veracity of such shall one day vindicate the vigilant and the virtuous.
Verily, this vichyssoise of verbiage veers most verbose vis-a-vis an introduction,
and so it is my very good honor to meet you and you may call me V"