I found pipe cleaners are great to play with when waiting in lines. You can pick up packages at the dollar store.
Use the mini M&M tubes to keep quarters and pennies for pressed pennies. Purchase a pressed penny book when you arrive to immediately put the pressed ones it. You can usually find the books near the cash register. My kids had a great time collecting them. You can use Canadian pennies, but need US quarters.
Use fastpasses!! Get one even if you aren't sure you'll use it. If you don't use it, just pass it on to someone who will (they'll love you for it!)
Give each child a disposable camera to record their view and moments of Disney. Gives a different perspective.
Purchase glow sticks from the Dollar Store before you leave. Bring them out when waiting for Fantasmic, light parades or fireworks. This way you won't have to purchase the very expensive Disney light up things, and the kids just love the $1 glow sticks.
Go to the left. Most people go to the right in lines.
If you get a Pal Mickey, purchase a water bottle holder (they have them at Epcot) to put around Mickey and then you can wear him around your neck or over your shoulder. This way you can hear him and he won't get misplaced.
Finally, as Scratch said, go with the flow! It'll be busy and crowded, and most people aren't as informed as us DISer's!! Take time to sit and relax and people watch.
Have a great time!