Well, the word "Parelli" will cause a lot of heat here on this forum. Some will say he is the equine devil, and others will swear by his every word and action. I don't know very much on the Parelli method, so I don't care either way for him or his wife's training techniques.
Personally, I would look into finding a trainer, a riding instructor, or an experienced horseman to help you out. It's easy to learn what you are supposed to do, but actually carrying out the task can be challenging.
In personal exerience, I always thought I was the isht when it came to horses. I watched all the hollywood horse movies, I read countless books, and took G-d knows how many pony rides at the carnivals/ fairs. Heck, I even rode an elephant when I was three, I "knew" everything about horses.
Then I started taking lessons.
It turns out keeping your heels down is a lot easier said than done. And knowing the difference between the cantle and pommel didn't do squat for me when I started learning to trot and lope a horse.
The reason the transfer from paper to practice is so hard is this: 1.
Every horse/person is different and 2.
You may not understand the entire consept to begin with. Just like every person is an individual, every horse has its own way of thinking. Just because you can replicate everything the man did in the video/book down to the tiniest detail, doesn't mean it is going to be the perfect approach for George. And yes, there are going to be instances where you aren't going to understand entirely what the author/filmmaker is saying, but you can't ask questions to the book/video and magically get the exact answers you are looking for. This is where another more experienced horseman becomes invaluable. They can tell you ways to adjust you techniques so George understands, and you can ask questions to them, and get the answers you are looking for.
Don't get me wrong, videos and books can be REALLY helpful to you. You can learn a training technique or a different way to ask for a responce you hadn't thought of before. They will broaden your resourses for training and working with your horse. But, having somebody there to guide you in your learning process will make it that much easier to understand what you are learning.
Hope this helps!!!