I find it easier to caricature someone after I have done blander more "realistic" studies.
Boy, anatomy is filled with so many mysteries. I think someone would have to spend full time studying for a few years before beginning to understand how everything fits together. Otherwise, you end up just drawing superficial copies, like what I'm doing. Little by little some stuff starts to make sense, but I'd really need a good teacher to explain what's wrong and to physically correct the drawings in front of me.
One mystery is how all the mouth area fits together.