I'd like to redraw this bigger (it's a small sketch on an old sketchbook) but I'm blind to my own mistakes. The mouth area doesn't look right neither does the ear placement. I followed Loomis construction with some plane knowledge which is perhaps a still too fuzzy still. I suspect I need to have a firmer understanding of the skull underneath.
Any other blatant mistakes you can see? Eyes too big?
Also, I'd like to know what studies do I need to make to be able to turn his head around, up and down, tilt and etc so it looks exactly the same person every single time, because I fail at this. How do you "own" a character's face, so to speak? What artists do this flawlessly and why?