You have some pretty interesting designs and a good, eye-catching sense of color. My biggest critique though (and I gripe about this a lot) is to learn proper anatomy and proportions first. It won't come naturally and takes time, but it's worth the end product of having anatomically-correct, styled drawings.
I commend you for having the shape/joints in the legs correct! A lot of younger horse artists tend to make them too like canine legs. I do have to say that at least your horses look like horses... I've seen some pretty bad horse drawings in my day. Like the one(s) below! :P