Training should be a fun experience for you and your dog. He learns some new tricks, you learn how to communicate with him better, and the bond is strengthened on both ends of the leash. If you and your dog are both having fun, then the dog will be much more engaged. Move around, use a lot of verbal praise in addition to the food and toy treats. Find the right motivators, having something that really turns your dog on can make the difference in a dog that wants to repeat behaviors and a dog that is yawning after one rep of an exercise. Keep training sessions very short and do more short sessions throughout the day instead of one long session, use lots of reinforcement and make it very high value, in the form of enticing treats and toys. If you lose your dog, then do something very short and easy that you are sure your dog can do successfully, and end the session on a positive note. Playing with your dog can also be a reward. Sometimes you need to get very creative as a trainer.