Please just post what problem you are having, and I will try to answer. I am best at equines, fur, hair, and linearts. ^^

Sorry if this isn't the right place to offer help. >.<

I use a pinkish purple, and go on the inside of the lines. It also helps to realize where the shadows should be longer. Set the layer to multiply.

For regular shading~

I use a impression brush on about 5-10%, and go over the area until the highlight looks strong enough. Then I use an impression blender at 5-10% as well, but I go over it just until it is blended enough to look consistent. Don't over blend, or it will be blurry. This goes for both highlights, and shadows. Highlights I use white, and shadows I use black. They should be on different layers. Set both highlight and shadow layers to overlay.

For fur~

I use a specially designed fur brush, but it's really nothing more than a clump of streaks. I do the same method with highlight and shadow as the regular shading, but instead for fur I try to layer it. Always start from either the front or the back of the animal. I usually start at the head. Be sure to put fur shadows under large clumps of fur.

I hope this makes sense. :3

Cna you help me with equine anatomy