Disneyworld suggestions?

I’m going with the wife and two kids (ages 3 and 6) to Disneyworld for the first time tomorrow. We’re going to Orlando because my wife has a conference, so we’ll probably hang with the kids for a couple days at the hotel, and hit Disneyworld for 2 days also. Any suggestions for must-do activities while we’re there? Epcot I hear is a must-do. Anything else? Any suggestions for discount admission/tickets? Thank you!