Pure stupid luck
I personally like the 2nd photo in post #29 a lot better and am a bit ashamed of my mediocre performance today. Both of Kristinas photos use the frame a lot better then mine, and don't even get me started on picking my background.
Still, thank you for the kind words. The photo has some good aspects as well. I caught all of Amy as well as the frisbee in the frame. Also picked a favorable framing to get the sand in the focal plane, preventing this typical "my dog is flying high" look. Also managed to leave a bit of room in the direction of movement. It also helps the image, but I'm just not a fan of the full silhouette look. The image might have benefitted (a lot) had I moved 5 meters to the right, picking Amy in a 1/4 frontal angle. That would have resulted in an image with some serious 3D pop to it.
(I'm quite critical on my own photos. That kind of is the fun in having a partner who is also a talented photographer. I measure my photos against Kristinas and find the good aspects of hers, compare those with the bad aspects of mine and already I found a thousand ways to improve my photography. I like the challenge in this)