4. Understand that Epcot is a Very Large Place
You can expect to do a lot of walking when you visit Epcot, just as you do with the other three parks in WDW.
The trip around the World Showcase alone is more than a mile, and the distance from the park entrance to the back of the World Showcase is just a little under a mile. That should give you an idea of how much stepping you'll be doing, especially if your route takes you back and forth across the park and/or in and out of the various pavilions and shops around the World Showcase.
The moral of the story here is, bring a pair of comfortable shoes to wear—you'll need them.