I purchased Jane Davenport's new book, Beautiful Faces (Drawing & Painting).
In one exercise, Jane suggest painting some ovals on a page and adding two curved guidelines (horizontal and vertical) on the ovals. Next, place facial features on the guidelines.
Since my watercolor paints were not nearby, I colored my ovals with a yellow highlighter - and then added the details. Jane's book is very comprehensive and jam-packed with great techniques. You may want to check it out.