The absolute best tool you can have at your fingertips is an itinerary. The best plans start at least as early as the rehearsal, include where everyone is staying overnight (with contact phone numbers), and cover play-by-play "day of" instructions for every member of the bridal party in as little as 15 minute increments during the peak busy times.
Who needs a copy of your itinerary? EVERYONE!!
(Starting with the obvious) your planner/coordinator, every bridal party member, parents of the couple, the officiate, the caterer and any other vendor(s).
However, an absolute MUST is your DJ. They will be key in keeping your celebration on track because they will be announcing those special moments. Remember, there's power in the microphone so be sure to utilize that power to keep your guest aware of what is happening and coming up next so they don't become confused or bored.
Final thought: A well planned event is a happy event!