It occurs to me that training is more about learning to understand another species than it is about "mastering" that species. It's about trying to understand what your animal thinks whether it be dog, cat, horse...whatever.
The other day I was working with a client who has taken on the challenge of training two litter mates together. The "boys" are 8-month old Aussie/Border Collie mixes and have been clicker trained from the start. Now they are old enough to start what I would call the real work of learning stay. These pups have all the necessary foundation training to succeed, however, to young male dogs stay a totally foreign concept. And, that's OK.
One of the toughest things to teach a dog is stay...it makes no sense to them whatsoever. We humans like stay because it can become our invisible tether. Dogs on the other hand don't see the point. So how do you bridge that gap? Well, first I try to begin the process of teaching stay where the dog will be most comfortable. That could be a favorite spot in the living room, or a sunny patch in the yard. The point is that if you work in a place where the dog is comfortable and is willing to stay on his own, you help the dog understand what you want and make it easy for him to do it.
After I explained how to practice and incorporate favorite spots, my client's comment was "I would have never thought of that." There are so many other ways you can use understanding your dog and his temperament and personality to help make the training/communication pathway easier. If your dog loves going for walks on a wooded trail, do that instead of walking in a neighborhood to practice loose leash walking. If your dog prefers to down on soft pillows or rugs vs. the hard floor...work with it. Once you communicate and proof the behavior in a place the dog is willing to "play the game," you can move to other locations with much less effort.
Bottom line, remember, you dog has emotions, likes, dislikes and knowing what makes him tick will make the job of training and communication just a little bit easier.