Much of dog training is putting your dog into or keeping your dog out of behavioral ruts. k9disc is no different. Change things up frequently to keep the game exciting. Many dogs will grow bored with a set sequence, and you will have to work to get them to really shine within that sequence that is boring to them.
As handlers, we all need to be careful to not force repetitive failure on our dogs. Nothing will confuse a dog more than repetitive failure. The easiest way to avoid this problem is to switch things up when a behavior starts to fail. Move on to something else, and try again later. Of course you could opt to predict and reward the behavior, but the important thing is to stay away from repetitive failure.
Sometimes our dogs will lose focus on a trick, skill or behavior. Be flexible enough in your training and your game to react to this by giving the dog what it needs. If the excitement level has peaked, and the dog is too excited to perform, shift to something of a lower excitement level, and if the dog is bored, maybe a quick tug is in order for building excitement.