Dr. Horwitz, a Veterinarian says:
Finding the appropriate training takes some time and research because there are few if any regulations on dog trainers. First, ask other dog owners with well trained dogs where they attended classes. Next, go and observe to see if the training techniques are humane and productive. Beware of training the uses punishment, neck collar corrections and relies on having you "dominating" your dog. Most dogs learn best with positive reinforcement training; praise and food rewards help motivate the dog. Have some idea of what you want your dog to learn. If you just want your dog to walk nicely on a leash and obey basic commands you will want a class that focuses on those things. Finally, if you are in a class and the instructor asks you to do something that you are not comfortable doing, leave and go elsewhere.