Play is fun for your dog and it helps to build up the relationship with you. Some of the playtime can be by chasing each other, tugging with a rope or playing with a squeaky toy.
If you are playing with your dog outside you need to stop your dog playing or running after other dogs or squirrels.
Some playing suggestions are:
Concentrate on the game with the toy rather than the dog; don’t push the toy towards the dog’s mouth. Pretend the toy is a special, delicate animal and occasionally drop the toy and snatch it back.
When you notice your dog is tiring, especially small dogs or puppies, let them sleep.
More importantly, stop when YOU are tired.