Most books that teach drawing have demonstrations that look something like the sketch above (taken from this source). They begin with an oval-ish shape, horizontal and vertical axes, short smudge lines placed in strategic positions to represent nose, eyes and mouth, and so on.
They begin with the idea of a whole face, a regular or typical face, a norm. They specify very simple directions that promise to be easy enough for anybody to learn.
They are okay, as far as they go. I wonder when I see them: are people really this afraid of making mistakes? It’s just a drawing.
If you want to draw, but are afraid to draw, try rules like these to get past your qualms and your reluctance. But that said, the recipe for faces is a very inadequate approach to drawing. Really, to be truthful, it’s an awful approach. It is completely reliant upon very limited, conventional ideas of what a face should look like. It holds no hope for anyone who wants to explore his or her own sensations of seeing.
If you want to draw, your first challenge is just picking up a pencil and beginning. But if you are brave from the beginning, you will reap benefits later on. Forget ovals and proportions. Imagine instead that the object of your attention has lines wrapped around it. Imagine placing your pencil upon one of those lines and copying it upon a sheet of paper. Do not even care (in the beginning) overly much whether your lines match these lines in nature. Just try (very hard) for the nearest match you can get.
If your lines cannot match at first the spectacle of what you see, at least have them be your lines. What you saw, what you felt, not the recipe for conventionally considered faces.