I always find it a most expressive pose whenever a dog cocks their head to the side. To me it communicates curiosity, or the dog's attention has been captured by the viewer or both. Coupled with the open mouth "smile" this red kelpie really looks like he/she is hamming it up for the camera and that creates an instant appeal for the viewer. I like how the dog is captured with the great outdoors as the backdrop. However, I wish the lighting played more evenly across his/her face. The right side falls a little too much into shadow when I think that the rich tones of the Kelpie's color would really shine if it was evenly lighted.
What a happy looking dog...great capture of that smile! My only suggestion would be to be sure that the eyes are in focus. In this shot the nose is better focused than they eyes which I think takes away from the image overall. Hope that helps.