right now I am just aiming to get proportions down, I done an exercise of drawing cyclops from the book You can Draw Marvel Characters by Dan Jurgens.
Nice start, try to construct heads based on cubes, not curves that sit arbitrarily in space. Start with a cube and carve the curved surfaces out of it, while checking if symmetrical landmarks line up with straight perspective lines (corners of mouth, eyes, etc). Keep it up!
just remeber that everything is in perspective in figure drawing. I wouldnt even start figure drawing unless i had a solid grasp of perspective. Draw faces from reference untill you can do it in your sleep. And be VERY familiar with the skull
Blahm's right, practise drawing cubes in perspective, and then use alignments projected onto them to find the correct proportions in perspective. Then, use something like this as starting point, don't worry about features yet (based on Bridgman):
Heya! Your studies are really going well, keep at it! ( I need to start studying anatomy too come to think about it). It might actually be useful to try to sketch the skull and other structures in different angles, like you did, as well as under different lighting conditions (underneath, above.) this will help your shading technique as well as your anatomical understanding. Double whammy!
I wish you all the best,
I don't really have any suggestions to help you... maybe trying different time elapsed on each drawings ?
For exemple doing a very long one aside shorter ones ?
In any case, keep drawing alot. That's the only way to get better.