YUS

xDDDD

The whole outline and design seems rather good, as in I like how you did the coat hair etc. looks rather accurate.

I would start by working into the shading a lot more (though you might already have been told this). For example, on the hair you should have a range of dark and lighter tones like how you did at the base of the skin on his legs.

As for his coat, I can see you've done a checkered design but usually shading with light and dark tones is more favourable (dark in the inner arms, and gradually going lighter on the tops of his arms. However if you wanna checker it I ain't gonna stop ya xD

One last thing is that skin tone tends to be lighter (for Benedict Cumbebatch anyways), and often it will have undertones of either yellow or pink. What that means is that the skin will either be slightly red or slightly yellow.

Here I made it slightly pink, and here more peachy yellow.

Those are just a few tips I have for you there as I can see you are really eager to improve :)! Either way keep up the good work ^^