I notice that you are great at drawing teeth. I guess all that extra effort paid off. For me, the toughest part were drawing the hands in different poses and sometimes drawing a unique looking nose would get me .
Thanks man! If I'm honest, teeth, hands, and noses, all give me trouble as well. I spend a lot of time drawing and erasing until they look somewhat realistic. Just can't go too dark right away, as that always makes it more difficult.
When I was younger, I actually started with more of a comic-style influence, drawing full body illustrations. However, after struggling with proportions, hands, and feet, for many years, I realized I wouldn't have to draw them as much with portraits, haha! I guess I have more patience trying to get facial features accurate, as they all play a role in capturing a likeness.