Updated: Aug 14, 2018
Some dogs love food...any kind of food...any time. Their stomachs seem bottomless. Other dogs could play fetch or tug all day long. Some dogs are driven by any word of praise from their handlers. Other dogs seem to like none of the above. There is a way to motivate your dog in training, regardless of your dog's breed or age. The key is understanding that what is rewarding is in the eye of the beholder. There is no cookie cutter approach.
First, whether your dog likes food or toys, you need to experiment to find the BEST food/toy and reserve that for training purposes alone. This makes the food/toy extra special to your dog. I find that meat treats are some of the most highly prized among food-driven dogs. Chunks of chicken breast, slices of deli meat, hamburger, etc. If your dog likes toys, is he driven by the noise of a squeaker, does he like to tug, or is he into retrieving? Does he have strong prey drive? Experiment to see what your dog likes above all else. Food-driven dogs can often become interested in toy rewards by using a treat dispensing toy, such as Kong's Lotus ball toy If he still isn't excited, attach an old leash to this treat-holding toy so you can drag it along the ground. This triggers the prey drive in many dogs, enticing him to follow and pounce on it. Now you have a toy that would excite almost any dog!
Now that you are witholding the most special treats and toys for training only, also check to make sure that your dog is actually hungry and mentally prepared to work. Did he eat in the last few hours? Consider making him work for his meal through training exercises, or delay his meal so he is actually hungry you train. You can give him his meal after training. Similarly, is he thoroughly exhausted from playing all day with other dogs? Or did he just get back from a run? Occasionally, physically exercising a dog can make him more focused on you and less so on distractions, but in other dogs, it can make them too mentally exhausted to work. Make sure that he is not already mentally or physically exhausted. He must be ready to work in order to have a successful session.
Another factor is to consider how you are interacting with your dog during training. Dogs often mirror our emotions and energy level. Are you exuberant? Are you positive? Do you use strong body language to convey how happy and excited you are every time he performs the correct behavior? I encourage people to be OVER THE TOP with this. Throw your arms in the air and exclaim, "YES! Good Boy/Girl!" the exact moment he performs the correct behavior and immediately reward with the treat/toy. This helps to build your relationship with your dog to where he actually WANTS to work for you, not where he feels like it is an obligation.
How are your training sessions structured? Are you setting up your dog for success every time? There is nothing more demotivating for a dog than repeatedly failing at what you are asking him to do. If they do not get the reward and praise, then they lose interest. If you are providing an attractive reward and he still is not demonstrating the behavior, then he probably does not understand what you are asking him to do. If your dog gets frustrated during a training session, back track to a simpler behavior. Have him perform several repetitions of behaviors that he knows well and reward/praise him heavily for every repetition. As I said before, there is nothing more frustrating or demotivating than not getting the reward and praise. Consider a different way to teach the behavior, even breaking it down into baby steps (shaping) if needed. If you are not sure how to do this, a reinforcement based trainer can help you. Once you learn how to shape a behavior for the first time, you will realize that you can teach your dog to do almost anything if you break things into small enough steps that are heavily rewarded.
Lastly, consider what your dog actually wants to be doing instead of whatever behaviors you are asking him to do. Would he rather be sniffing right now? Playing with other dogs? Wrestling with you? Digging a hole? Scratches under the chin? These things can also be rewards that reinforce the behaviors you are training (Premack Principle). I typically don't use them as a primary reward during a training session. I rely on treats/toys/praise when the dog exhibits each desirable behavior. However, allowing the dog to do what he actually wants to be doing at the end of every training session can help him to de-stress, and it increases his focus during the session if he comes to expect that this is the final reward at the end. He will work harder for you with better focus instead of trying to steal away to sniff, play, chase birds, etc.
There is hope for training even the least motivated dog. It just takes a little work on the front end to find out what interests them. Training is about more than getting your dog to do what you tell him to do. It is about relationship building. It is about building a relationship where your dog is motivated not just by food/toys, but to work for YOU. This investment of time in finding a strong motivator is just learning more about your dog, and it pays off in the end.