This is a 30x40 painting that I started today. Below is an 8x10 plein air sketch which I am referencing for color and values, though the scene is different.
I started out by sketching in the basic forms and shapes with an old #2 bristle brush. I tend to save my old beat up brushes for sketching, and keep the better brushes for use later. Shadow shapes are outlined and filled in with diagonal, parallel lines. This helps me remember what is a shadow and what is not.