I'm about to reveal what you must know in order to intelligently choose a professional dog trainer. Okay, let's begin. A good dog trainer will use techniques and training styles which are compatible with your dog's temperament.
Every dog is different, and some dogs respond better to certain approaches.
What works for a Rottweiler won't necessarily work for a Poodle. Don't measure a dog trainer's skill by his number of years in the profession. Instead, judge a trainer by what he has done in the 'Dog World,' rather than how long he has been doing it. Some need more time to learn than others. When professional dog trainers train their own dogs, they never do it in a group setting.