OK, to make a long story short, I want more "keepers" when I shoot sports. My son plays football. I stand on the sidelines and try to capture images of him in action, etc... I get some keepers, but just as many out of focus captures to toss. What gives? Could use some pointers. Not looking for better equipment. Just looking to nail focusing more often. D800 & 70-200 VRI I use "C" continuous and I've tired 9 points, 51 points, 3D, etc.. can't seem to master this aspect of shooting.