How about what to wear when at fair? I did that and it was pretty easy. I also dressed up in my western show stuff and my friend dressed up in her English show stuff.
Or maybe the different kind of horse shoes out there. Like the light weight and sometimes glued on aluminum shoes race horses use. Or the rounded egg shaped shoe that is used to correct. And examples on when to possibly leave your horse barefooted and such.
Or you could probably do it on blankets. When to blanket your horse, the different types of blankets, and even fly sheets haha.