We are big planners when it comes to Disney. We book our Advanced Dining Reservations as soon as we are able, then plug all the information into an Excel spreadsheet, which we print out and take with us. That way we know where to be, and at what time.
We realize this may seem a bit stiff for some, but for us, dining is a BIG part of our Disney trips, so we don't mind planning our days around restaurants. We do try to plan for some "free time" to add flexibility.
Whenever you book a reservation, the Disney representative will give you a 12-digit confirmation number. While we've been lucky so far, it is possible for a reservation to get lost within the Disney database. That's why we always hold on to our confirmation number. You just never know.
So here's how an itinerary of ours looks for a week at WDW:
And here's a close-up:
On the far left we insert categories, then fill in the columns accordingly. Each column is dated, and the information is filled in. There is room for the names of the restaurants, the location, what time the reservation is, and the corresponding reservation confirmation number. Sometimes we'll add a row titled "Events" where we can record special things, such as a night we have tickets to the Mickey's Not So Scary Halloween Party or have booked the Fantasmic Package.
Here are some itineraries we've made from past trips (click on them to enlarge):