I started by working out the drawing on paper at the actual size it will be on the canvas. This is not a detailed drawing. I want to make sure the proportions are close to accurate, but the main idea is to establish where the images will go on the canvas. Note the grid lines that I will duplicate on the canvas to ensure the placement is as intended.  

After I transferred the drawing to the canvas, I will start roughing in the painting, focusing mainly on the darks first. I determined that the background needed to be somewhat established before beginning any serious detail on the figures. I'm continuously correcting imperfections I catch in the drawing as I go. I am also flushing out the problem areas that aren't defined well in the photograph. In the original photo, the chief had his arm at his side and not extended, so I had to invent the wrinkles in his shirt, which is a bit of trial and error. I also added the second rider to the photo using Photoshop, which really helps make the perspective believable.

This image shows my progress. I have worked on most areas, but I see many areas that need refinement. I haven’t done much to the grass except add some yellow, which is too chromatic at this point. Next, I will put some darks in the grass and go over it with more natural colors.  

The final result