I think you're on the right track, same as Paint. (: How old are you?
I don't want to critique and set the bar too high ... both of you are fully capable of drawing silly cartoons with horses, such as LilRuffian does. Little comic strips are PERFECT for practicing expressions and some angles.
As with Paint, I'll gladly give you more in-depth help when you need it. I gave Paint a couple of tutorials (on proportions/how to draw & breaking the anatomy down into simple shapes), I'm sure she can show you them so I'm not spamming the forum with them constantly. :P