Other than rides -which the majority of people, myself included, like the thrill one's the best- (FastPass everything you can!) here are a few of my tips that I can think of right now:
If you buy things in the parks definitely have them sent to your resort room or at least to the front of the park for you to pick up on your way out. It is so easy to do.
Character meals really are so much fun for all ages and they have a nice variety of food. My fav's are MK's Liberty Tree Tavern, Contempory's Chef Mickey's, and the one in Norway at Epcot (Princess). It also saves you the time and hassle of trying to meet characters in other places.
Don't skip the shows. They give a nice break from walking and rides and are great. My absolute favorite is Festival of the Lion King at DAK. Just be careful where you sit or you can be a chosen one (sorry Dad!)!! The Nemo one is okay to, but I liked Tarzan so much better. Epcot has lots of smaller scale shows in the countries tucked away. The train at MK is also a nice way to take a break.
It is really fun to sit in the front car of a Monorail train. Just ask nicely and you may be able to do this.
The parades and night shows are excellent. Try to schedule your days so that you can see each one if possible. Don't miss Fantasmic! or well any of them lol.
If you only have half a day then go to Downtown Disney and the West Side. There is lots to see/do there like DisneyQuest, shopping, movies, lots to eat, and boat rentals (the water mice are so much fun!). The Boardwalk also has many fun places and activities to see, not just at night. Of course the water parks are lots of fun too (I like Blizzard Beach better for the rides).
Most of all, enjoy every minute of it but don't stress. What you can't get to this trip will most likely be there next time
Have Fun!!!