Knowledge is a daily pursuit. What you obtain, you keep for life. Breeding horses successfully takes Knowledge and lots of information.
Balance is the first consideration when evaluating horses.
Mentally I divide the horse into 3 parts, remembering that each part should blend with the next, and ALL parts should look like they belong on the same animal. Good legs and proportionate feet. Must have good temperament. Croup, long and fairly level with a long straight tail dock that flags upward and is carried high. Trot, movement that covers ground with cadence, where the joints open freely and are not restricted.