Looking pretty good overall. A couple points to consider: The close ear needs another line to give it shape, right now it looks like a solid cone. The right foreleg seems a bit thick at the top compared to the rest of the leg. On the tail at the ring, you should have the hair bunch up on both sides of the ring. Below the ring is fine, just add some volume above it. I agree that adding a part to the hair somewhere might help it look less helmet-like. If you're going to add all those little wrinkles to the edges of the socks (I think you could do with having fewer) you should have more of them affect the silhouette of the leg, like you did at the top of the sock. It will help add more depth. Also don't be afraid to add larger folds that actually cross more of the center of the leg. I question the amount of detail around the hoof, it seems a bit too well-defined for being covered by a sock, but maybe it's supposed to be a very thin/skintight sock.
Keep at it, you're doing good. It's fun watching your improvement.