When the action starts, don't take your eyes away from the viewfinder. This is true for wildlife, sports, small children playing, and many other things. As soon as you look at the subjects directly -- not through the camera -- you lose the precious milliseconds it takes to refocus and recompose if something great happens. Even if there is a lull in the action, keep looking through the viewfinder and you'll be ready to instantly go into action yourself by pressing the shutter and shooting. These sparing elephants in South Africa gave my photo tour group and I quite a show, and the only way I was able to take many wonderful pictures was to watch the entire 'performance' through the camera. That way, i didn't miss a thing. I used a 1/500th of a second shutter at f/7.1 with an ISO of 2000. I used the high ISO to ensure the shutter was fast enough to freeze the movements of the elephants. I used the new Canon 100-400mm for this pictures.