Drawing this angle

At 90 degrees, use the profile as one continuous path from forehead to nose, lips and chin. Compare where each part projects and where the contour recedes. Avoid constructing the face as a stack of unrelated symbols: a convincing nose alone will not correct a chin placed too far forward or a forehead leaning at the wrong angle.

Leave enough room behind the ear for the back of the skull. That mass is easy to shorten when most of your attention goes to the face. Measure the ear's position against the brow and nose, then follow the jaw from chin to its corner beneath the ear. Notice where the front and back of the neck meet the head. Use the tonal drawing to separate the side of the face from the under-jaw plane. Try a silhouette study before adding the eye, keeping its visible shape narrow enough for a true side view.