Being here in the western U.S. in cow ranching country, we don't see our horses as pets, other than the kids ponies. They are working partners in getting the job done. Having said that, in terms of breaking horses or correcting bad behavior(s) we learn quite well from those that have had success in dealing with it previously, in this case my father.
The key to any behavior modification is consitency. One simply can't apply any corrective behavior on a hit or miss basis. Secondly, for example, if biting is the problem. I've never had a horse yet that didn't telegraph what he or she was going to do. A bite from the horse should be met as soon as it's perceived by the rider. That is, if, for example, your standing at the horses side preparing to mount, you should be aware the moment his head turns toward you and meet that motion with a quick elbow. Not a hard hit but a firm "blocking" motion that gets his attention. Only a little practice will help you be aware of the horses intent.... This is just a quick discussion of how one should discipline such a large and relatively intelligent animal... in my opinion...