There are two kinds of NH, for all practical purposes.
~NH as simple, common-sense riding and management, relying on the use of simple, universal equipment and solid, step-by-step training to accomplish the ultimate goal of a quiet, willing, responsive horse is one type.
In my mind, good dressage falls under this umbrella. No, there is no "carrot stick", no "games" to play, but it is still a simple (just not easy), systematic training method, predicated on the foundation being solid, correct, and complete before moving on to more difficult concepts and movements.
I find that most horsey people, nearly all on this forum, nominally NH or not, take this type of approach. It's just horsemanship, plain and simple.
~NH as a discipline unto itself is the other kind; I.e., buy this
DVD's, and NEVER deviate from the plan, and you're "doing natural horsemanship". I'm not meaning to bash any specific brand or clinician, they all do it to some extent. This kind might (and has) screwed up some horses - not through the fault of the method, but through faulty application by practitioners who need more than DVDs to become proficient and effective.
The problem here is primarily the idea that one can become a horseman from watching DVD's alone. It's like learning karate by mail - yeah, possible, but there are a lot of obstacles that are hard to overcome without some real feedback. You learn the moves, but not the theory (at least not as well). It's hard to replace a good instructor or coach (or mentor, if you're interested in becoming a trainer yourself) with a DVD.
Another problem is the notion that "THE PLAN" will work for every horse in every situation, and to deviate from it is percieved as heretical. I do hate to beat a dead horse on this... the pros and cons have been discussed, debated, and downright argued into the ground in other threads.
As far as advice goes, read on theory before practice. Look up Tom Dorrance, Ray Hunt, and some of Monty Roberts' and Pat Parelli's early
work. Cherry Hill's short book How to Think Like a Horse
is worth a read as well. Learn equine body language, and practice "reading" what the horses around you are telling you.
Sit on a fencepost at your pasture and just watch. Take notes - who is the boss of the herd, and how can you tell? Who is the lowest rung of the herd ladder, and how does he behave? How do they interact, and make their feelings and preferences known to each other?
As far as practical "NH" techniques, watch and read everyone, nominally NH or not, the good, the bad, and the ugly. With a firm foundation in the theory of why and an ability to read equine body language you should be able to take techniques that will help you and leave the fluff and tripe behind. If at all financially/logistically possible, enlist the help of an instructor or coach to help you sort through new things and help you learn the correct application of tools and techniques. You *can* self-teach (I did, and still am), but you're back to Karate-By-Mail: it takes a lot of discipline and research, and you will make mistakes with horses as you learn.
Sorry for the novel... I get to rambling sometimes. Best of luck!