I took a day off from doing commisions to practice drawing heads. I mostly focused on figuring out a way to draw better, more interesting eyes, and how to do them at different angles.
Some warmup faces (bleh, ugly) and some eyes I drew while figuring out how to construct them in 3d.
The 3 eyes that are somewhat shaded were quick studies from photos.
Even if you can draw pretty eyes it doesn't mean a thing if you can't place them correctly on the head. I did these to practice exactly that. Plus it does not hurt to draw some heads at different angles once in a while.