1. Get to the parks early. Beating the crowds to many of the rides sure beats waiting in lines all day.
2. Plan your use of Fastpasses, but get them when you can. Why wait in line for 70 minutes when you can get on and off in 10? You can only have one Fastpass per entrance ticket per time slot. If you have non-riders in your group, use their tickets to get more Fastpasses. We worked the system really well at Magic Kingdom where there were 12 of us, but only 5 that were into thrill rides.
3. Make reservations for meals. No matter how resilient you are, you'll want to take a break and sit down for a while. You are going to have to eat, so you might as well reserve a spot at a restaurant. Without a reservation, you'll have to eat on a bench or more of a fast food type restaurant. Either way it's going to be expensive, so you might as well enjoy it and rest at the same time. We got lucky with our reservations, you might want to book ahead of your trip.
4. Get some fannypacks. My family made fun of me for my pack, but it was big enough for sunscreen, band-aids, lip balm, wallets, and two water bottles. I had people asking about where I got it. The guidebooks recommend them too. Fannypacks are less cumbersome than a backpack and when you get on a ride, you don't have stow it to keep from losing it. Instead you just turn the fanny pack around to your front. It also gave me good support for my lower back. My wife's fannypack was a little smaller, but between the two of us, we carried everything we needed.
5. Plan ahead. Know what rides or shows you really want to see and make them priorities. A lot of the more popular rides end up with really long waits. It's also not much fun standing in line with children, inching forward slowly, while Fastpassers zip by. We had a lot of success following the plans laid out in the guidebooks. The girls' princess makeover was booked well in advance and so was our Chef Mickey experience.
6. If your children want to meet Disney characters consider one of the special meals. You are guaranteed to meet characters at the meals. They will also pose for as many photos as you want. The character meets in the parks are more like an assembly line. The people in line want you to take your one photo and then get out of their way. Not to mention standing in line for autographs and photos eats away at your time for rides or shows.
7. Bring your own water and small snacks. No surprise here, but everything is a bit expensive in the park, so save yourself some money and bring things with you. You'll spend enough money on the park itself and souvenirs, so any way you can save is well worth it.