To use this technique effectively, the photographer needs to be able to anticipate where the action is going to occur. While you can't always know, there are some assumptions you can make. If you're trying to photograph birds in flight, you can expect that you'll be better off pre-focusing to a far distance rather than a close one. If you're shooting sports, take a risk and pre-focus on a spot where you think the next action is going to take place. If you're photographing a baseball game, key on the pitcher or the catcher first -- you know they're going to be part of the play. If there's a runner on first, pre-focus on second base in anticipation of a potential stolen base. If there's a runner on second or third base, pre-focus on home plate in hopes of a play at the plate. For football, consider down and distance and, if possible, use your knowledge of the team's tendencies to pre-focus on likely action spots. For first down, focus on the backfield since there's a good chance of a running play and handoff. On passing downs key on an area within range of your lens that produces first down distance. For basketball, pick an area a few feet beyond the rim. These choices will put you in the right place often enough to improve your shots. You won't always be right, but your results aren't measured by your average photo, only your best shots. The idea is to aim for home runs, not singles if I can use a sports cliche.