This shows a bit more work on the shadows and muscle structure. On the underneath of the horse's belly where there is a slight graduation of color in the shadow I will blend the paint while it is still wet. I mix the lightest color and the the darkest color of the graduation on my pallet. (I use pallet that keeps the acrylic paint wet as it is notorious for drying out too quickly!!!). I then lay down the lightest color all over the the area I want shaded.
I then pick up the darkest color (usually a smaller amount) and start at the point I want the darkest point of the shadow to begin and I blend it in working my way down towards the lightest point. As the initial layer is lighter and still wet you can get a nice graduation as it picks up the lighter color underneath as you work you work your way down. I do this until the the paint appears to be the same color as the initial layer you put down. This whole method can be worked in the opposite way i.e. lay down the darkest color first and blend in the lightest. I find it is better to put down the shade or color that will be the majority and then mix the other in.
This horse has lots of spots and does look quite flea bitten as you can probably see from the ref. pic. I call them his freckles. To do these I spotted the paint down using a very fine brush as you can see in the first image.