Konrad Most began training dogs for police work in Germany, and was appointed principal of the State Breeding and Training Establishment for police dogs in Berlin, where he carried out original research into training dogs for a broad range of service tasks. At the outbreak of war in 1914 he was charged with organising and directing the use of dogs to further the war effort. He headed the Experimental Institute for Armed Forces' Dogs during the Second World War, and afterwards ran the German Dog Farm, a centre for the training of working dogs, including assistance dogs for the blind. He played a leading role in the formation of the German Canine Research Society and Society for Animal Psychology.[10] His 1910 publication, Training Dogs: A Manual, emphasised using instinctive behavior such as the prey drive to train desired behaviors, advocated the use of compulsion and inducements, differentiated between primary and secondary reinforcers, and described shaping behaviors, chaining components of an activity, and the importance of timing rewards and punishments. The book demonstrated an understanding of the principles of operant conditioning almost thirty years before they were formally outlined by B.F. Skinner in The Behavior of Organisms.[11] While publishers of the 2001 reprint warn that some of the "compulsive inducements" such as the switch, the spiked collar and the forced compliance are unnecessarily harsh for today's pet dogs,[12] the basic principles of Most's methods are still used in police and military settings.[13]
Based on the principles of social learning, model-rival training uses a model, or a rival for attention, to demonstrate the desired behaviour.[69] The method was used by Irene Pepperberg to train Alex the African Grey Parrot to label a large number of objects. McKinley and Young undertook a pilot study on the applicability of a modified version of the model-rival method to the training of domestic dogs, noting that the dog's origins as a member of large and complex social groups promote observational learning. The model-rival training involved an interaction between the trainer, the dog, and a person acting as a model-rival, that is, a model for desired behaviour and a rival for the trainer's attention. In view of the dog, a dialogue concerning a particular toy commenced between the trainer and the model-rival. The trainer praised or scolded the model-rival depending on whether the model-rival had named the toy correctly. It was found that the performance times for completion of the task were similar for dogs trained with either operant conditioning or the model rival method. In addition, the total training time required for task completion was comparable for both methods.[70]

Just because your new dog is old enough that he should know where to potty doesn’t mean that he actually does. An adult dog has the necessary muscle control to hold it for longer periods of time, but if no one ever taught him the potty training rules then he’s the equivalent of a brand new puppy. Age should not be equated with housetraining prowess, so it’s a good idea to treat any dog new to your home as if he’s still learning the potty training ropes.
There is nothing inherently wrong with telling your dog “no,” except that it doesn’t give him enough information. Instead of telling your dog “no,” tell him what you want him to do. Dogs don’t generalize well, so if your dog jumps up on someone to say hello and you say no, he may jump higher or he may jump to the left side instead of the right. A better alternative would be to ask him to “sit.” Tell him what you want him to do in order to avoid confusion.
Before enrolling with a particular club contact them and ask if you can go to watch a class without your dog. This will help you decide if this is the right environment for you and your dog. Some clubs have waiting lists and you will need to book ahead, some accept people on a roll on roll off basis. Prices will vary from a joining fee and then weekly payments to a one off fee for a certain length of training.