These drawings were made in a few minutes. I used the technique of a renowned water colour painter, David Rankin. He wrote an article called: 5 minute recipe for drawing faces. http://davidrankinwatercolor.macmate.me/David_Rankin_Watercolor_Site/Faces_files/Sketching%20Faces%20Faster.pdf .
Earlier this spring I had explored and trained his method a little, using pictures. And adapting it a bit to my own taste. But essentially it's all there. Check for yourself.