If you think about the face as an egg shape, you can mold the features into it. The cheekbones, chin and brows protrude, and the eyes sink in. The nose comes out, obviously, but draw the tip as ball and realize the edge you're drawing isn't the middle of the nose, but the side of it. If you practice drawing it all out with sharp geometric angles, it'll help you get a feel for the dimensionality of it. Proportion is the only other issue, so try to find a measuring system that gives the best result. Lastly, remember, you aren't drawing a face, you're drawing a 3D form in the shape of a head.

Hope that helps! I still have a lot to learn too, but this is how I think about the forms. It's important to try to memorize the dimensionality of things, not the individual features.

Pencil and pen.