Realized that one big mistake I made yesterday was rotating the plane marking the side of the head, rather than just changing it's angle against the y-axis (technically, that's also a rotation. But whatever.) so I tried again with the face pointing more and more to the right. And then I flipped over the paper, and started it all over. This time with more circle and ellipse guides and rulers. Still struggling a bit with the looking down faces this way, but it's sooo much better now.