During a training session, your dog should succeed at least 80% of the time. Successful training requires protecting your dog’s confidence. An unconfident dog will struggle because he lacks motivation.

“Why should I bother? I never get it right anyway.” is what a dog is probably thinking when he tries to do something but still doesn’t get that treat).

Remember, the key to training is your dog’s ability to recognize that he controls his decisions, and that his decisions control his rewards.

So if your dog is struggling during training and the rate of reinforcement (i.e. the rate at which you give him treats) falls below 80%, you should work on some other behaviors that you know he can do to bring that rate back up. Take a step back temporarily and work on an easier or less distracting version of that skill. Or play a completely new game. Just make sure it's roughly 80% wins.