The head studies continue and boy, I realized they're a bit tricky to nail. Going through Uldis' book, they divided the head mass into two parts: a cylinder for the face, and an egg for the skull. Actually it's three parts if you include the neck (but that's just another cylinder).
Previously, I'd used to think to think of the head as a cube in 3D space (and even before that, just a circle) but I didn't quite nail it as seen here. But once I've started applying the cylinder+egg shapes, it began to make sense. I combined my awareness of the cube and cylinder+egg shapes by quickly drawing a bunch of different angles. I realized that it works as a neat foundation (albeit not that accurate, yet).
An added note is that I realized that I forgot that there is mass under the chin so I definitely forget drawing that especially for back views of the head.
I'll head over to specific head parts (eyes, ears, mouths, nose) perhaps for the next study hour.
Reference used:
Anatomy for Sculptors - Understanding the Human Figure