I have studied Charles Sovek's book, Oil Painting, develop your Natural Ability fairly extensively. The style he used to write his book made him seem somewhat approachable. When I didn't quite understand something in one of the lessons I emailed him my question (on a whim, not seriously expecting a reply). Sovek not only replied right away he included an instructional drawing attached to his email to explain his answer more fully! What a guy! I was very sad to learn that Charles Sovek passed away last year. His book is a fantastic legacy, however, and sure to go down as one of the best art instruction books of all time. An early exercise in his book asks you to think about your scene in only warm and cool. Using just orange and blue (initially) you can clearly see the overall design of your composition and easily organize the painting. I revisited this exercise today and painted this orange/blue warm/cool painting below.