You never draw a face freehand and hope. You build a light scaffold first, drop the features onto it, then rub the scaffold away. Same handful of moves every time, whether it's a careful portrait or a two-minute sketch.
The Moves
First, draw an egg or oval for the whole head — slightly narrower at the chin, wider at the cranium. Second, rule a vertical centre line straight down it; everything is symmetrical about that line, so it keeps both halves honest. Third, mark the eye line halfway down — the rule from rung one — and place the eyes there. Fourth, split the face into rough thirds: hairline to brow, brow to base of nose, base of nose to chin. Those two extra lines hand you the nose and the mouth almost for free. Drop the features onto the guides and the head assembles itself.
A Few Measurements Worth Knowing
The thirds give you the heights; a couple of widths finish the job. The eyes sit about one eye-width apart — and that very gap is, near enough, the width of one eye, which is why you can use an eye as your measuring stick. The whole head is about five eye-widths across, so there's roughly half an eye of space outside each eye before you reach the edge. And the ears run from about the brow line down to the base of the nose, which is a handy check: if your ears are floating up by the eyebrows, something's drifted.
Let the Guides Do the Placing
The trick — exactly like sending box edges to a vanishing point last term — is that you never guess where the mouth goes. The thirds already decided it. Build the scaffold accurately and the features fall onto it; the live check in the toy turns green when a feature sits on its average guide and amber when it's drifted, so you can feel the grid working before you trust it on paper.