A good trainer understands his dog
The best times for training a dog are in the early morning. This is because a night's sleep helps the dog since all of his senses and nervous system has been resting. This allows the animal to be more willing to work with a trainer. It is important to not stereotype the animal and to always use a specific type of training or order of exercises. If the dog's order of training and exercise is constantly interrupted it can cause the dog to become disoriented since he will start to pay more attention to the changes that constantly happen rather then to the training. A dog must not be forced too much. There is such a thing as too much. If the training become too intense the dog will become tired and stressed and the effect will no longer be parallel. In some extreme cases it has actually caused
If you are having problems with your dog during your training sessions together then you should sit down and review what it is that you are doing and how you can improve on your techniques. If you are not sure what to do then ask a friend that has a dog and experience with training to sit in on one of your training sessions as an observer to help critique what you are doing.
If all else fails you can approach a animal training expert or animal behavior expert to ask for help.