I have worked as a dog trainer for over ten years and am always developing the way that I train and work with dogs.
I find that using positive reinforcement is the best way to teach owners how to work with their dog as it builds a strong relationship between a dog and its owner as it strengthens what the dog is learning. There is often a misconception that positive reinforcement means using food rewards frequently to reward the dog. However, this is not the case you can literally use anything that your dogs loves including toys, scent work, verbal praise and physical praise. The more you reward a dog the more eager it will be to want to work with you - I always think of it as a bank account the more you pay the more you will get out of your dog. All dog's can learn through positive reinforcement techniques it may just take a little detective work to find out what your dog loves and may take a little trial and error when you first start out. It makes it a pleasant experience for both the dog and their owner!