I train my own horses as well as train at a training facility for clients under a much more experienced trainer.
I can honestly say the WORST horses that come in for training are the ones who were "trained" by their owners who didn't have enough experience.
IMO, you can't read a book and go train a horse. A good training method comes from years of experience and knowing what to do next if something isn't working. This almost always requires a mentor in the beginning...someone who will push you enough to not hold your hand the whole time, but also knows when to step in and tell you what to do next if you just can't figure it out.
It's more than commitment, consistency, and patience.
It's knowledge, experience, common sense, good timing, and knowing when to push or lay off. It's compassion, always being a step ahead, and alert because in training, ANYTHING can happen. It's being savvy enough to know when a horse is ready for it's first ride and knowing when the horse is in the perfect place to stop for the day. These are all things no one will learn from a book or watching a TV show.