Playing fetch with your dog can be rewarding for you both. You get to interact and play with your pup, and he gets to introduce you to his favorite toys as you toss them out into the world for him to go find.
Playing fetch with the dog doesn't always mean you get to do it more than once. Sometimes you toss the ball or a rope out across some expansive space, expecting your dog to bring it back to you, only your dog runs very excitedly to retrieve it and stands on the other side as if mocking you, refusing to let you have it again. This, of course, puts an end to your game of fetch. Teaching your dog to bring a toy back to you is the second phase of training your dog to play fetch. If you want to toss a ball more than once, your dog is going to have to know how to bring it back to you so you can throw it again.
Dogs who understand the second half of this fun game are eager to bring their toys back to their owners so they can, of course, play again. Dogs who just want their toys to be tossed out for a wild chase and then to hold on to them don't quite get that this game is one of enticing intrigue. You will need to teach your dog that he gets to play the game over and over again by bringing back the toy. This might mean you need to trick your dog into believing he only has one toy, and you happen to have it even when it's in his mouth. This also might mean you need to get your dog to chase you, making yourself an intriguing part of your game together.
Training your dog to bring a toy back to you is going to involve encouraging and enticing your dog. To do these things, you will need to have some high-value treats and identical toys on hand to make trades. You may also want to look into getting two of the exact type of toy. So two tennis balls that look exactly the same will work, or two ropes that are exactly the same will also work. Put your running shoes on and be prepared to run around with your dog, including running away from him to encourage him to come find you with his special toy. Turn this into playtime and bonding time with your dog and have fun with it.