[AlagaesianDragon]

My example is not so good, but hope I that it helps!

~ Curve the neck for a more elegent, Arabian horse look
~ Make the eye more oval and add eyelashes if you like
~ The belly and back curve a bit, but not too severly. Imagine the back as a slightly bent pole. The belly just depends on how chubby you want the horse to be.
~ For some character, curve a leg and make them a bit skinnier. I have definately found that smoothing helps.

These are just basic edits, but I hope that they help.

Eye image..
http://nevadaequineassistedtherapy.com/wp-content/uploads/HORSE-EYE2.jpg