I photograph dogs whenever I want to practice photographing sports. Their owners usually don't mind when you photograph them, since strangers who love dogs are not perceived as threats. And if you can find a beach where dogs can play off-leash, you'll have lots of opportunities to shoot some fast action.
Follow The Snout: As with people, try to photograph your subjects when they are facing into the light. In Photo #1, the dog is looking into the light. This Visla happens to be my favorite "dog in motion" photo for the simple reason that this pose could not possibly be duplicated in a static environment. Definitely, a dog in motion.
I know that some day, another dog will come into my life, and fill the emptiness left by Jocko, the dog that would define my relationship with nearly every other animal that would cross my path. Until that time, I'll be content to enjoy other people's dogs as my parents loved their grandchildren: unconditional, unlimited, and eternal.