It's Implied

Here is my portrait study. The features are implied with the dark values. I like this study. Not a lot of detail but you know it is a man's face.
I learned to put the side planes and top plane of the nose down, test the highlight at the tip of the nose and skip a line along the edge. The highlight on the forehead is, also, placed. The skin between the nostril and the lip on the light side is almost a tear drop.
I didn't need to define much with the ear nor the eyes.