Our must-do character meals are Chef Mickey's (breakfast) at the Contemporary Resort and CRT (lunch), Crystal Palace (lunch), Liberty Tree Tavern (dinner) - all located in the MK.
The other character meals we currently have scheduled for this year are breakfast at Donald's Breakfastasauras in the AK, lunch at Garden Grill in the Land Showcase at EPCOT, and breakfast at Princess Storybook in the Akershus Restaurant in the Norway World Showcase at EPCOT.
To determine which character meals are right for you, go to allears.net. The site lists all the current character meals at WDW w/ the characters normally present at the meals & the menus of the restaurants.
Once you determine which ones you would like to try & determine your touring schedule (what parks you're going to visit on what days), then try to schedule the character meals as soon as you can. Some character meals get booked more quickly than others. And it's always better to call earlier because then you have your choice of times.