Try TourGuideMike!
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www.tourguidemike.com
You have to pay for a subscription for $21 I think. It last until 6 months AFTER youre arrival date. After buying 3 (yes 3) guidebooks I finally decided to check out TGM and EVERYTHING I could possibly think of was on there. Plus, he has each and every exact date of the year with the best parks to visit on that date due to crowd levels and special events so you can just plug in your travel dates and most of your planning is already done with! He also has all the rides in each park categorized by how busy they get at certain times in the day which makes your daily itinerary easier to plan out. An example would be "First thing in the morning: Dumbo, Space Mountain, Splash Mountain... After lunch: blah blah blah" so you just sit down with your party and ask them what they want to ride and pick out a few from each category.
Go first thing in the morning
I planned an itinerary for the mornings in each park (1. Winnie the Pooh 2. Its a small world, etc.) and DBF and I went to Magic Kingdom on our first park day and RAN to Fantasyland and rode every ride with the longest wait being 8 minutes! It was amazing. DBF had zero interest in Fantasyland but once we got into the "zone" of being ahead of everyone else he was really excited and was like "whats next on the list? Peter Pan? Lets go!!!".
Maximize those Fast Passes!
As another person on this thread pointed out, most CM's will let you ride any time after your fast pass window begins. We would go around collecting FPs in the morning and we would return to our hotel for an afternoon break and when we came back to the parks at night we got right on some of the busiest rides, one right after the other.
No matter your age, take the time to visit some characters
DBF and I are college kids but that didn't stop us! I waited 45 minutes in line at Toon Town to meet Cinderella, Aurora and Belle and MAN was it worth it! The whole time in line I was thinking "ugh i wish I didnt decide to do this" but once I got up to the princesses I was SO glad I did. They were my cutest pictures (Theyre each in these cute velvet tents so theres no random people in the back of your pictures) and they were all there together, meaning really, I waited 15 minutes for each if you broke it up which is really shorter lines than any other character I'd met up until that point. Also, a GREAT place to meet Mickey, Minnie, Donald and Goofy is Camp Mickey Minnie in Animal Kingdom. If you go during a showing of Festival of the Lion King (great show btw) there are ZERO lines. In fact, when we walked up, there was no one waiting for Goofy and he RAN up to us and gave us a bug hug and dragged us back to his photo op place to take pictures! We spent a whole ten minutes with him and got some hilarious pictures!
Be kind to Mousekeeping!
On the plane ride to Orlando, DBF and I colored envelopes for Mousekeeping tips (They'll only accept tips if its marked for them) and left thank you notes. They adored them and left us several notes about how they liked them and in return we got towel animals! They left us a note on our last night thanking us for being so sweet and told us we could take home all of our towel animals (14 of them total!!!) including a mickey balloon they left for us.
If you're taking a backpack
If you're taking a backpack to the parks, put everything in it BEFORE you leave for Disney World and just put it in your suitcase, that way you know everything is there and you don't have to worry about forgetting to put something in there when youre running out the door half asleep to make park opening. Also, if you use all of something, replenish your supply as soon as you get back to the hotel so you don't forget after that nap!
Make Copies
Make copies of EVERYTHING. the back of park tickets, flight confirmations, dining confirmations, resort confirmations, everything. Leave a copy with a friend or relative at home too so if something happens, you can just call up your pal and get the information.
Have a great trip everyone!!! And remember, let loose! This is the only place where its ENCOURAGED to act like a kid!