I’ve witten before about how it is important to know the sport you are photographing.  This helps to anticipate where the action is going to take place and be proactive rather than reactive and potentially missing the shot.  This not only applies to the photographer on the the sidelines, but the players on the field as well.  Some of my favorite photos taken at a recent soccer tournament are of the anticipation in the players faces and body language as they prepare for a play to unfold on the field.