Hi Nancy!
Welcome to the Disney Parks Moms Panel. Your princess will have the most magical visit at Walt Disney World! You'll have a few different options available to locate Disney Characters in the Parks. Firstly, check out the following
Character Experiences link on the disneyworld.com website. Be sure to have an account set up with My Disney Experience on the site, as well.
Selecting any of the experiences listed will then provide you a "reminder" in "My Plans." For instance, let's say your daughter adores the movie Beauty and the Beast. You can select the Beauty and the Beast - Live on Stage, select a time you think would work with your plans, and a "reminder" will be saved when you pull up your itinerary under "My Disney Experience." It's not a reservation, but a reminder of the shows or character greetings you'd like to add to your plans. Meeting Princess Tiana in Liberty Square would be another example of a greeting you might wish to add to your plans.
If you're carrying a smartphone into the Parks, downloading the My Disney Experience App will also provide you an up to date listing of which characters are greeting guests throughout that day. Look for the "Characters Today" feature. If you do not have a smartphone, a paper Times Guide is available at the front of each Park listing the same information.
My final suggestion, Nancy, is to book Character Dining experiences. Check out the following
dining link, offering over a dozen options to meet characters. Advanced Dining Reservations are highly encouraged as early as 180-days prior to arrival.
I hope my answer was helpful and please don't hesitate to ask any other questions coming to mind.
Best wishes!
Sherri