This has been a fascinating thread. There are a lot of great tips and tips that you can read here. I wrote a long time back some tips. Since then we have amassed some new ones that hopefully are different then some of the other ones that are repeatedly mentioned.
1. Clothes: We like to utilize the washer & dryers on site (in room is better). If we stay at a resort with onsite W/D, then we do wash half way through. If we have one in our room (DVC member), then we do wash every night or every other night. This REALLY reduces the amount of stuff we have to pack. Also,
purex washer sheets are really fantastic for travel.
2. Packing Cubes: I travel a lot for work. Over time I have learned the value of these little wonders. So when it comes time for us to pack for any trip, my wife puts everyones clothes in a pile and I pack it. We have 4 kids (9, 6, 4, & 1) and while the little ones clothes dont take up as much space, we have to pack 2x as much for them as they constantly are going through clothes. One time we all went for 5 days and all our clothes fit in 2 standard size carry-on bags. My wife was impressed.
3. What are we doing next? Many times we go with family or friends. I tend to be the one who obsessively plans out the entire trip. Once I get everything somewhat finalized, I start getting requests to share that info with everyone At first, I tried all types of spreadsheets and complicated ideas. Nothing ever worked simply for everyone.
What I have found to be the best method to do this is to put EVERYTHING into a calendar, and then let everyone else subscribe to it. Most modern calendar apps support a variety of nice features: Alarms, hyperlinks (great for linking to park info or menus), phone and address, attachments (perfect for boarding passes or other important documents) and even map co-ordinates. Then I help everyone subscribe to it (preferably from a smart phone). Then everyone has access to everything. Typically I add what park we are going to, park hours, time/location of dinning (including reservation numbers), Flight info, rental car info, hotel reservation info, etc. I am amazed at the magnitude of info that I have been able to put into a simple calendar.
4. Planning:This one is to share with your non-disboard friends. Because I enjoy the planning of the trip, I am always getting asked by people who have never been to WDW about what to do. My number 1 recommendation is to spend an hour or two looking over a few sites and get a scope of what to expect. So many people I know go there thinking it is like a regualr theme park. NO NO NO. You need to go with a plan. To best illustrate this, the fist time we went (with 15 people) I didnt know you needed reservations for dining. At 7pm we decided to eat so I strolled up to some restaurant in the Canada section of Epcot and asked for a table for 15. The girl behind the podium delicately explained that they have been booked for months. There was a mad scramble as we quickly tried to find a place for very young children and seniors to walk to. I laugh about it now, especially anytime I try to get a reservation for 4 to Le Cellier. Moral of the story is a little planning goes a long way. I always feel bad for that group who is standing in the middle of the Magic Kingdom arguing because they dont know what to do next or where to eat.
5. Spread the Magic. One of the things that I love to do at disney is take pictures of my family enjoying the vacation. When we get home I alway notice that I am in very few to no pictures. And unless we do the photopass, there is almost never pictures of all of us. So a little game I like to play is to watch for other people taking pictures of thier entire group.... minus the one taking the pictures. Then I offer to take a picture of all of them together. It is a nice kindness that I enjoy doing for other people.... my hope is someday someone will do the same for us.
6. Souvenirs. So anyone who goes with kids can commiserate on this one. Kids want ever trinket, toy, shirt, hat, etc. On our last trip, my wife and I came up with an ingenious plan. Every time the kids said they wanted something we said, great, lets add it to the list. Then we would take a picture of them with the item. Then the night before the last day, we went through all the pictures and helped them pick out the one they wanted. We helped to guide them away from an item that would be to difficult to go back or an item that may not be the best value. This has saved us countless headaches explaining that they cant get everything that they see that they like.
As a separate (but related) tip, if you have access to a car. there is an official disney outlet store just a few miles from downtown disney. You can get a lot of disney stuff there for half price.