Basic Head Drawings Critique

With your anatomy drawings I think you are focusing too much on details such as facial features and fingers at this stage and not enough on the constructions of forms, which you should focus on first. They don't entirely match up with the proportions in Brunet's video. I'd try again and just draw the shapes like he did and don't worry about putting a swole six pack on them yet.

It's good that you've done the heads from lots of different angles. Don't forget that the front of the face is three dimensional too, try to imagine where the flat side of the head is on the opposite side and draw a nice curve between them. Don't forget that you can draw things you wouldn't be able to see in reality to help you construct the form and then erase those lines later.

If you are doing Marc's course on anatomy and I haven't taken it so I cannot provide any corrections from what your teacher may already be providing. I dont want to give you contradicting information.

I will say though that you have a lot of "petting" in your line work and not confidant strokes ( I address that below) and you are somewhat drawing the "symbols" for anatomy like letters for the alphabet instead of thinking of things in 3 dimensional shape/construction forms like adamjwass already mentioned.

But I can apply some Andrew Loomis Perspective over your head construction. I'll find errors I've made and replace the image here over the next week probably. Cheers.

Also you can find all Andrew Loomis Books on Archive.org placed there by various libraries.