I use the same technique to draw horses, that I use to draw homo sapiens. Namely, the head height as unit for measurement. Served me well in this acrylic study as well -
28" x 22", acrylic on paper.
And here is the W.I.P sequence:
- The drawing in charcoal - just a basic shape outline with some suggested value changes
- The drawing lines 'inked' over with burnt umber (mainly) and prussian blue.
- Added the background (imaginary).
- Painted a transparent layer (leaving a few areas paper-white), to understand the tonal variations.
- Opaque layer partly added
- The finished painting as above.
Ref image by Breathless-dk in DA.