How about a pathfinder feat-
Preparation-Feat-You may take up to 4 hours of preparation and spend 10 gp for materials to prepare for an event in game. This event can range from a fight to an ambush. When you do, you gain a +2 preparation for the first round of the event on all d20 rolls. This bonus drops to +1 on the second round, and is lost by the third round.