I second the latter approach -- are you staying on property? Is it an early entry day at either resort?...That first hour of early entry is amazing - do as much as you can as fast as you can, don't arrive late.
BUT -- that being said, DisneyCane's advise will only work if it is NOT an early entry day at Epcot if you are a Day Visitor -- the resort folks will fill up all those lines during the first hour and when you enter you will already find 40-50 minute waits.
If it is a plain old non-early entry day, and all you are looking at are the highlights, then start with EPCOT and book your fastpasses for Magic Kingdom.
Get there 45 minutes before rope drop and you'll be at the front of the entrance line...once in, head directly to Soarin' -- do not stop to pee, do not stop to retie shoelaces, just book it immediately there. Ride Soarin' then head immediately to Test Track and do Single Rider immediately, skip the designing your car part, go directly ahead on in...then go next door to Mission Space and ride (there will never be more than a 5 minute wait in the morning no matter which side you pick. Now backtrack to SSE (if it says 25 minutes, the wait will really be 10 minutes -- they are stacking times now on here for some bizarre reason known only to WDW), then backtrack and do Livin' with the Land, The Seas with Nemo, and backtrack back to do Ellen's Energy Ride. You will be done with ALL OF THESE by 11:00 a.m. You can pick up Figment if you want, or make reservations for lunch in World Showcase.
Book your Fastpasses for MK and go there SECOND -- the biggies for Fastpass are 7 Dwarfs Mine Ride, Peter Pans Flight, and Splash Mountain. You will not need fastpasses for Space Mountain, Haunted Mansion, or Pirates -- AFter you have ridden the rides on your fastpasses, you can book ADDITIONAL fastpasses for Jungle Cruise or Space Mountain or anything else that looks good at the time. You can book even MORE fastpasses on busy days if you want after that. Be aware that 7 Dwarfs, Peter Pan, and Splash RUN OUT OF FASTPASSES if not booked in advance -- the others can be added in the parks except on the very busiest 10/10 crowd days'