Hey there!  I took this post down, because I’m going to redo this section; ultimately, I didn’t find it as helpful as it could have been.

I’ve found that drawing the head starts to make a lot more sense once you start thinking about cheekbones and cheeks, and how the fit into the head structure.

You might be aware of the Mysterious Indent that Looks Good Next to the Outer Part of the Eye, or the Mystery Indent for short. 

Drawing a Mystery Indent may serve you fine if you only draw the head from flat angles, but it falls apart when you get adventurous.

Why isn't this making sense anymore?

Drawing a ‘Mystery Indent’ is an attempt to imply cheekbones without knowing how they actually incorporate into the skull, and this is why it looks so unconvincing when you use it to draw the head in anything other than 3/4 view.

The cheekbones wrap around the head and eye sockets from above the bridge of the nose.  The concave you draw if you draw the ‘Mystery Indent’ is a misunderstanding.  There is no concave.  You should instead be thinking of this as where the eye socket/brow overlaps the (convex!) cheekbone.

Compare the cheekbones on both sides for placement.  They should match up and correspond with each other.

(Knowing cheekbone structure helps when drawing gaunt characters, because their cheekbones may stick out.  Remember to compare the cheekbone placement on both sides!)