Joanne at in Art posted interesting thoughts by Edgar Whitney on painting watercolor portraits.
Read the book here.
Whitney talks about the nature of watercolor as a medium and the need to avoid overworking. Freshness is the goal. for stitched portraits. A watercolor labored over loses freshness. But the other issue is likeness. How to get a likeness but maintain freshness. Whitney says it takes 5-6 attempts to get down the shapes/elements. After 4 or 5 studies he has the architecture down. To achieve freshness, he works quickly.