We all know that to make an area appear lighter, make the area next to it darker. This idea was reinforced at the OPA Exhibition in Fredericksburg, TX when Kenn Backhaus painted for us with a fantastic demonstration. The image was of a building with an archway; I think it might have been a cathedral. The sunlight streamed brilliantly across the face of a portion of the wall leaving more than half of it in shadow. "To make an area appear bathed in sunlight it has to have a strong contrast of a dark area. That area should be larger than the light area," he said. I'm paraphrasing here but I think I am close to his actual words.
This 11x14 was so much fun. I completed it in less than three hours. No underpainting, just laying blocks of color shapes of light and dark with some mid-tones.