An oekaki I did a short while ago:

I always admire people to do oekaki, especially such an amazingly detailed oekaki.

colour and art wise I have nothing to add... but I would suggest puffs of mist for both horse and the rider to show they are... breathing. Maybe it is just me, but I feel the horse's proportion is very good, just I think the legs should be longer a tiny bit. Just some thinkings...