Hey Fish, these drawings are pretty solid. Proportionally they're definitely correct enough. What I would say is that you probably should spend awhile just drawing circles, lines, and swaths of tone. So much of traditional art is dexterity based. It can be frustrating switching from digital to traditional, and vice versa because you're losing essentially all of the dexterity you've built with your medium of choice. I'm sure you've heard that advice before, but the longer I draw the more I realize that circles and lines are the holy grail of practice. Hope this helps!