Hey
This is a really nice start, I'm sure this can get somewhere!

Overal it has very low contrast. I'm not sure what the light souce is from the helmet, the shadow seems to suggest it's from straight above. Why is his right foot lit if it's in the shadow? Why does the cane look like it's lit from the left? Why is he so dark, where is he?
As for cleaning up, you're right that it becomes mushy. 
Try to work with some pixel perfect straight lines for the dagger, on both sides it can be easily tweaked to be a 1-1 and a 1-2 line.

Why so many folds on his legs pants? It can do with a lot less. Removing those unnecessary details can be a nice contrast with the furry edge of the coat.
His shoulders seem to be extremely broad, try overlaying the bones and see if it still matches up. Especially his right (our left) is way out of proportion.
What is his left hand doing? Is it pushing against the wall? Could be made more obvious also from the angle of his arm