I finished the running horses commission. Here are the step-by-step photos of the drawing. Milo is generally unhelpful during the drawing process.
I have previously done drawings like a printer, going left to right in 1 inch swaths to avoid smearing the charcoal. I have changed my process recently though. I now draw more like Photoshop, using layers. I made the outline of the horses and then shaded in the main items in the piece leaving out pieces like the manes which overlap the background. When I begin shading the background I leave space for the manes to be lighter than the background. Then I do the sky and clouds. After everything is done I can add the mane because the hairs are above the sky. When completely shaded, I look at the entire drawing to see if the overall shading is consistent. I usually get so bogged down in details I have to make sure that some of the tiny details are not too obvious or too light compared to other parts. In this drawing you can see that I initially had the black horse considerably shiner than he should have been. I finished out the drawing by reducing his shininess.