First, I am by no means a Disney expert. I am not paid by Disney nor any other Disney affiliate. I did however do my research and have a few ideas to share with you.
First of all, the BIGGEST easiest way to save money is going off season. Disney has several different "season's," but anything that says "value" is good and cheaper.
Try to stay in one of the value resorts. They are still really nice and are even available for larger families. It's also possible that you could stay in adjoining rooms if necessary. There's a brand new value resort opening in the summer of 2012 that will be Ah-MAY-ZING! It's called Disney's Art of Animation Resort. They are already booking nights there, so if you have a trip coming up I'd say for sure see if you could get a room there.
Always wait for a special offer. They always have them, you just have to watch for them and check their ending date. A good way to know about the offers is to sign up to get Disney emails. They don't send a bunch of extra junk mail and you'll be among the first to know about any good offers that would be good for your family. We did the "kids stay and play free offer and saved, count it, $900+. Wowzah!!
Always ask for free upgrades once you are at the resort and checking in. You heard me. Sometimes you can get a better view, nicer room, or even a more upscale hotel. You can also always pay for an upgrade too. Sometimes at a discounted price once you're there.
Do online check-in. It saves time.
Get a dining plan. Any of them are good, and you can often get them for free with your stay. It's a good special they run just about all year long. We got the deluxe this last time we went and were able to eat at all the character dining places and get two snacks a day and we got refillable mugs. Look at the different plans and be sure that you don't get too much of a plan, but also that you don't too little. You don't want to get there and not have enough meals left to eat somewhere you want to go.
Use the park schedule to find out where you'll get extra magic hours. You get extra hours in the parks when you stay on the resort. We were never able to use the night-time extra hours, but the morning hours are great. We planned our days in the parks by going to the place where the extra hours would be. Once you have a plan try to stick with it. This will help you be sure to see everything you want to see.
Plan for three days in Magic Kingdom. That's enough time to see everything there. If your time in the resort won't allow you to spend that much time there, know that you will most likely be able to see everything you want to see, so make a list of the most important things for your family.
We only ever spend about half of a day in Epcot. You could spend more time there if you wanted, but for families with small children plan to get there at opening, see what you want to see and end your time with lunch with the princesses at Akershus. Good food, nice atmosphere, and a LOT of princess fun!
Animal Kingdom is like a glorified zoo, but has several must sees. Skip on the animal walk-thru's and do the safari, the parade, and FOR SURE watch the Finding Nemo and Lion King shows. We spend a morning and afternoon there. It's plenty of time.
Once you've seen both Epcot and Animal Kingdom you can hop over to Magic Kingdom as long as you have the park hopper option on your tickets. This is a MUST, I think and totally worth it in my opinion.
Hollywood Studios is fun and there are lots of things to do there for little ones. You for sure want to be part of the pixar pals parade because it's the only place to see many of the pixar characters. The new Toy Story ride is OK, but not worth the CRAZY long(90 minutes) wait. There is a fast pass for this ride, but it's still likely to take all day. We got there at 10 and the fast passes weren't until 3:30.
Fast passes and parent swaps are GREAT for families on busy rides. Most of the busy rides have fast passes. A fast pass allows you to get a ticket to ride the ride at a particular time(a 1-hour window). Fast passes used to be able to be used any time after the time as well, but they are really cracking down on this rule now. Still the hour window is nice. There is still sometimes a short wait, but nothing like what it would normally be. The parent swap pass is available at any ride and allows parents to wait in line together and then simply swap out. For instance since the babies in our family couldn't ride the 40inch rides Scotty would ride the ride with the girls first and then he'd get a ticket that would allow us to skip the line and I'd go with the big girls for my turn. A really nice perk of WDW.
When planning your meal reservations be sure to give yourself breathing room. We felt a little pinned down by our reservations any time we had three in one day. Try to either do breakfast and dinner or and early lunch and dinner. Our favorites are 1900 Park Fare(breakfast with Alice and Wonderland and Mary Poppins and dinner with the Cinderella characters.), Cinderella's Royal Table, and Akershus. Other great places that are quick dining are Pizza Planet in Hollywood Studios(a MUST SEE for anyone who likes Toy Story) and Pinocchio's house in Magic Kingdom.
Make sure you see the Electric Magic Parade, light show, and the fireworks at Magic Kingdom while you're there. The fireworks are every night, but the parade and light show are only on certain nights. It's a MUST SEE.
Fireworks show at Epcot is not worth staying for in my opinion, but you may want to see if if you've never been before. Be sure to get there early, because it's really hard to see if you aren't in just the right spot.
Watch the Magic Kingdom daily parade in Frontier Land. The crowd is so much better there and the characters all had time to stop and shake hands.
Take your own water bottles and fill them in the parks.
Take a cheap poncho. It rains most every day.
Take a flashlight if you are disoriented at night like me.=)
We brought our own strollers. The park has them to rent, but they aren't very comfy and are only for use inside the actual parks. There is still a LOT of walking to do outside the park.
Try to take a little time to visit downtown Disney.
Reserve meals before you go to be sure to get the best times, but if you get there and want to go somewhere but don't have a reservation you can most likely get in as long as you don't go at peak times. Before 11:30 or after 2 for lunch. Before 4:30 or after 7 for dinner.
Go to Mickey's Backyard BBQ if possible. It's a seasonal dinner show, but was the BEST dinner of our trip. We'll be sure to go back any time we are there. The characters come down and dance with the kids. SO MUCH fun!!!
Olivia says, "DO NOT GO TO HAUNTED MANSION!" Scotty was thrown off by the words "happy haunt." I said ARE YOU SURE??? These kids get scared easily. The girls were TRAUMATIZED! Happy haunts? Not so much!=)
Emma Claire says be sure to catch the Captain Jack Sparrow show in Adventure Land inside Magic Kingdom. It's right across from the pirates ride and a lot of fun for pirate lovers.
Addison says waiting in line to see Rapunzel is TOTALLY worth it. She's only in Magic Kingdom and only in one place. You'll have to wait in line, but seeing her is totally worth the wait.
Isaiah says look your cutest for the ladies so they'll give you LOTS of kisses and go see Handy Manny in Hollywood Studios.
Mia says she really likes the fireworks, but be sure to take your time in the day and allow for naps so your not to tired at the end of the day and end up sleeping through the show!
Hope this helps, friends! Let me know if you have any questions.