Disney World Tips?

Ashley • Astrophysicist TTC @ 33. Oliver & Alessa born/passed Sept 2008. Emma born Aug 2010. James stillborn Jan 2015. Sarah born Jan 2017.
We're taking our 3.5-year-old daughter to Disney World in Florida next week. Does anyone have any special tips or tricks? She's into all things princess. We've already got breakfast with Cinderella booked and Fast Passes done, but it's all so overwhelming. I just want her experience to be magical.