Cute picture and I like the composition. The only fault I can find with it is that the bright background distracts from your subject which is in the shadows. If you had used a fill flash to fill in the foreground it would have helped a lot. Your focus is also right on the dog's nose rather than the eyes. I don't know what the rule is with dogs, but generally I try to focus on a subject's eyes.
Someone more enlightened than I could give better advice since I am hardly an expert.