Work with a Disney-certified travel agent. 

I can't stress this enough: they're no cost to you and they will provide you a wealth of up-to-date knowledge and recommendations! My wife and I worked with Mouse Fan Travel [3] last time we went to WDW, and I recommend them highly. Your travel agent can give you suggestions on everything from where to stay to what to eat, and can help you make Advance Dining Reservations. — Quora user Michael Lee [4]

Make Advance Dining Reservations where you want to eat.

Disney's dining system is based on Advance Dining Reservations (ADRs). The window for ADRs opens 180 days prior to the beginning of your trip, so if you're going this spring or summer, you may have a hard time getting into the most popular meals (Cinderella's Royal Table, Be Our Guest Restaurant, Akershus breakfast with the princesses), but there's still plenty to eat there even if you can't get ADRs. — Quora user Michael Lee [5]

Use a Crowd Calendar to find out the busiest park times.

If minimizing wait times is your key priority, you should use a crowd calendar to see when the best times to visit are. But, Summer is always going to be pretty busy. Here is a great crowd calendar: 2017 Orlando Crowd Calendar [6] — Quora user Ian McCullough [7]

Use discount websites and travel companies to help you save and plan.

Check out Mouse Savers [8] for discounts and offers. Call the Walt Disney Travel Company for assistance with planning. If you give them your goals and budget parameters, they will absolutely work with you to help create the best stay possible.They can help you work through pros ands cons of different hotels, ticket packages, and the various rates associated with different times of year. — Quora user Ian McCullough [9]

Subscribe to the Touring Plans website.

Touring Plans [10] provides day-by-day recommendations for which parks to see to minimize crowds and waits in line . . . Touring Plans is a company founded by a guy named Len Testa, whose team tracks wait times and crowd levels, and reviews restaurants, hotels, and attractions on property. Testa's staff creates touring plans, or step-by-step suggestions for where to go in the parks that are designed specifically to minimize your wait in line. On the busiest days, they claim that their plans can save you three to four hours of waiting. You can either use their pre-planned outlines or design your own, and you can re-optimize them throughout the day based on what you've experienced and what the crowds are like. Touring Plans can also walk you through Fastpass+ recommendations. — Quora user Michael Lee [11]

Buy Disney gift cards at Target.

If you have a Target Red card, go to Target and buy up a bunch of Disney gift cards — you'll get 5 percent off with your Red Card since Target classifies these as entertainment cards, not gift cards. Thus, if you can afford to stock up on Disney gift cards, you can save 5 percent on as much as you'd want. — Quora user Tom Nikl [12]

For your first time at Walt Disney World, stay on site.

Disney's resorts come in several tiers/price points, so you can stay there for reasonable prices (Value), decent but not great prices (Moderate), or somewhat obscene prices (Deluxe). It's worth splurging on a nicer hotel if you can afford it, but you'll still get Disney magic at a Value resort!  With small children, you're likely to spend a decent amount of time at the Magic Kingdom, so consider the Polynesian Resort. — Quora user Michael Lee [13]

Save yourself the trouble and the cost, and ship essentials to your hotel.

Any essentials that aren't easy to pack and will cost a fortune on-site? Buy it on Amazon before your trip and ship it to your hotel. It'll all be waiting there for you, without having to lug it through the airport, check a bag, or pay a fortune for it on-site. — Quora user Tom Nikl [14]

Buy a Disney World guidebook.

Buy The Unofficial Guide to Walt Disney World [15] . . . The Guide will answer all of your questions about the World. — Quora user Michael Lee [16]

If you're staying on site, take Disney's Magical Express. 

Disney will take your checked bags to your resort for you, and you'll be shuttled there on a comfortably-air conditioned bus. If you arrive during the day, you're likely to experience minimal waiting time for the bus, too. — Quora user Michael Lee [17]

Get to the park early.

Get the clan up in the morning and get to the parks for rope drop! You can see so much with no wait at all while half of the guests on property are still asleep! Power through the morning, and then get out of the parks for the afternoon. — Quora user Michael Lee [18]

Find the characters you want to see by asking attendants where they are located.

If you're trying to see a specific character, the attendants at information booths have tablets they can use to look up where specific characters will be and when they will be there. — Quora user Ian McCullough [19]

Consider splitting up if you're in a group.

Consider splitting up the group from time to time, especially for character interactions . . . You'll be able to pick up a "Times Guide" with the park map at each park, and those will show character availabilities throughout the day. Don't discount when you'll see the characters out walking around, either! — Quora user Michael Lee [20]

Make sure to mention your special occasion.

Disney evidently noted that [it was our honeymoon] in our reservation and 1) mentioned it when we checked in at the Polynesian, 2) gave us a couple of "Just Married" buttons that every single cast member you see will acknowledge, and 3) left us a personalized, signed photo of Aladdin and Jasmine in our room when we arrived! — Quora user Michael Lee [21]

The shops on either side of Main Street USA in the Magic Kingdom are all interconnected.

If for whatever reason you need to move down Main Street quickly, you can beat the crowds by going through the shops. This is especially nice when it is raining or extremely hot, as the buildings are air-conditioned. — Quora user Ian Stainbrook [22]

Know which rides have short lines for when you feel like resting.

Knowing which rides at each park usually have short waits to get on, and also somewhat lengthy duration are a great way to give you and your feet a break: 
Magic Kingdom: Carousel of Progress, People Mover, 
Epcot: Ellen's Energy Adventure, Living with the Land boat ride,
 Hollywood Studios: Indiana Jones Stunt Spectacular, Lights Camera Action Stunt Show, 
Animal Kingdom: Wildlife Express Train. — Quora user Tom Nikl [23]

If you want to rent a car, rent it on property after you arrive.

Airport rentals are expensive, and you can probably get better rates from the on-site agencies. Renting a car gives you flexibility, and with small children, that's a good thing. — Quora user Michael Lee [24]

Eat when people ride; ride when people eat.

Make dining reservations for kind of weird times (early or late lunch, not at noon, for example). You'll be able to eat without waiting (you have a reservation), and you can ride things while everyone else is waiting in long dining lines. — Quora user Tom Nikl [25]

Get a Fastpass+.

Once you've made a reservation, when you are 60 days away from your first day, you can start making FastPass+ reservations online: Walt Disney World FastPass+ [26].

This is also where your "top list" comes in handy, so you can pick the things that matter most to you, which include character visits which you can get a FP+ for. Also, general tip for FP+: if you can get to the parks when they open (you should!), then avoid making FP+ reservations before 1pm. Ride lines are short up until about noon or 1pm, anyway, so save FP+ for 1pm —7pm which are always ride peak hours. — Quora user Ian McCullough [27]

Use memberships and statuses to get discounted tickets.

AAA members, active military and tour groups of 10+ can also get discounted tickets (through Disney).— Quora user Tom Nikl [28]

Don't overlook Disney's Hollywood Studios during Fantasmic!

I loved seeing the show one night of our last trip, but we were also there one other night during the show, and we rode the Twilight [29] Zone Tower of Terror about five times in a row with no wait. It was glorious! — Quora user Michael Lee [30]

Take advantage of Disney's Free Dining program.

During the fall, Disney offers a Free Dining [31] promotion for certain ticket packages. This was first instituted in part to try and attract more tourists during hurricane season. Booking this package will add the Disney Dining Plan to your ticket at no extra charge. — Quora user Ian Stainbrook [32]

Get out of the parks for the afternoon.

Florida's hot and humid, so either eat lunch in the park and head out for a nap, or head back to the hotel and find something to eat there. Then hit the pool, relax, and head back to the parks around sunset. You'll be refreshed and ready while you see hundreds of hot, tired families heading for the exits. — Quora user Michael Lee [33]

Don't buy bottled water.

Every food establishment will give you a free cup of ice water if you ask. — Quora user Tom Nikl [34]

Don't crowd into the Magic Kingdom for the Wishes fireworks show. 

Instead, head to the beach at the Polynesian Resort, and watch from afar (with the music piped in) and with a drink in your hand! — Quora user Michael Lee [35]

Make use of different kinds of transportation.

When you go to the parks, you're not always limited to just the bus system or the monorail. Some resorts have water taxis (boats) that will shuttle you from your hotel to some of the parks or Downtown Disney. — Quora user Tom Nikl [36]

Stay at hotels that have their own attractions.

Some of the hotels have the best restaurants and some even have awesome "attractions", like the live roaming animals at the Animal Kingdom Lodge [37]. If you schedule a rest and relaxation day, check out the surrounding resorts for all their hidden gems. — Quora user Tom Nikl [38]

Eat hearty.

Now's not the time to worry about your diet — at least, not too much. All of the walking you'll be doing will more than offset a cheeseburger for lunch, and that goes for the kids, too! — Quora user Michael Lee [39]

The Disney resort hotels are organised into different resort areas, so know your travel times.

Walt Disney World is much larger than Disneyland (it's about the size of a normal American city), and travel times between these areas can be significant, especially if you are depending on Disney transportation.

When choosing where to stay, factor in the location of the hotel within the property. Also keep in mind that different hotels have different transportation options. Some are serviced only by buses, while others have monorails and boats as well. — Quora user Ian Stainbrook [40]

Examine menus online before making dinner reservations.

Examine menus online before you make dining reservations, especially at buffet-style restaurants. In some cases, the menus at lunch and dinner are (roughly) the same, but lunch may be a big less expensive. Biergarten at Epcot is a good example of this. — Quora user Tom Nikl [41]

Beat Buzz Lightyear's Space Ranger spin game.

There are two targets that’ll help you win. In the first room, find the left arm of the left robot and hit it for 100,000 points. When you’re on Planet Z and you finally see evil Zurg, aim for the target at the bottom of his space scooter for another 100,000 points. — Quora user Tom Nikl [42]

Don't forget the water parks or Downtown Disney. 

Typhoon Lagoon, Blizzard Beach . . . Downtown Disney is also a great place to spend an evening perusing the shops and getting dinner. Just be sure you're prepared for a long walk! — Quora user Michael Lee [43]

Time your ride with the fireworks.

This one involves some careful timing, but one of my favourite hacks is timing a ride with the fireworks, particularly Jungle Cruise. It's a lot of fun being on the Jungle Cruise and looking up and seeing the fireworks in parallel. — Quora user Tom Nikl [44]

Take advantage of Disney pizza delivery services.

Disney resorts (typically) offer their own pizza delivery service to your room up until one AM. — Quora user Tom Nikl [45]

Get free samples of Coke in Epcot.

In Epcot and thirsty? Coca-Cola hosts a shop where you can all the free samples you can handle of different Coke beverages from around the world. — Quora user Steven Buehler [46]

Don't forget the most important thing of all . . .

The more magic you give out, the more it will be returned to you. — Quora user Mark Flory [47].