I know this isn't constructive or anything helpful, but I wanted to say I really like your second picture. His arm/muscles are really good and you've done the angle very well! I like his face too. Actually, maybe his head is a bit big compared to his arm? But I really like that picture nonetheless.
I think you have really great arm and face definition when it comes to shading.
and your digital aren't too bad. Don't be afraid to add more dark colors to you light colors :)
Keep up the good work.