I've decided now that I'm going to require all of my dog training clients to buy Peggy Tillman's book, Clicking With Your Dog. It's full of simple illustrations and breaks dog training down into very simple steps. I just don't see how one could not be successful using this book.
A lot of trainers want to come across as a rocket science who figured out the secret formula for training dogs. The truth is that we've known these principles in science since before I was born, and our job as trainers is to help people understand them and use them successfully.
I get very energized by seeing the transformation of an owner who is struggling with an "out of control" dog who is causing chaos in the household. It's such a joy to see the lights go on (for both of them) when they inject some structure (to prevent the environment from accidentally rewarding undesired behaviors), introduce the communication of the click and treat (marker and reward), and shape desired behaviors and habits.
Suddenly you have an owner who is delighted to be with her dog, and a dog who finally understands how to fit in and who enjoys a deeper level of affection. (I say "deeper" level since even though the dog was creating chaos and stress in the household, in most cases the owner still loveed the dog and showed that love. After training, the conflict goes away and life is MUCH better.)