Using the boxes and circles method again, I wanted to try drawing the horse looking up and alert. 

The more I do these the more I can see where the proportions are out. Here, I can see that the rear end of the horse is far too small and definitely needs beefing out. I also think the line creating the front of the chest is too far forward and pronounced 🤔

Using it as a rough guide I'm finding this technique really helpful. It doesn't guarantee spot on accuracy but at least I know I'm getting things roughly in the correct places.