Just search on the inter net on how to draw a good horse head, then type in how to draw a full horse!!!! It will help!
I spend a lot of time around horses so it comes pretty naturally to me. Go and look around at horses and look at their joints, proportions, how they move etc. Particularly their legs and head. That's what a lot of people go wrong on. :)
Drawing or sketching often comes naturally to people. Some people have a natural flair for it. Drawing a horse or any living object can be a difficult task as it involves capturing the being in its entirety, with its physical as well as living features. However, Here is a link that gives step by step pictorial instructions on How to draw a horse.