My best advice is to read, read, read. The best resources for planning are (IMHO) in this order:
1.DIS Boards
2.Mousesavers.com
3.Passporter (they've got a great new resource call passporter club at passporter.com)
4.Unofficial Guide
5.Tour Guide Mike
Other tips:
If you freeze your water bottles the night before taking them to the parks, make sure to wrap them with a washcloth when you go. The condensation will soak into the cloth instead of everything else the bottles are touching. Besides, it is great to have that cold wet cloth to wipe the back of a hot neck or forehead.
A great stay cool aid is those gel filled neck wraps. They stay dry until you soak them in cold water then tie around your neck like a cold scarf. They feel great on a summer day in FL.
Don't forget to pack scissors for moleskin. Moleskin is a wonderful product, but it is impossible to tear.
If you have naturally curly hair, plan for bad hair days. The humidity wreaks havoc with curls. Bring hats, visors, head bands or clips. The anti-frizz hair products work to some extent, but not 100%.
A cheap stoller cover for a double stroller is a vinyl table cloth or a plastic painters' drop cloth from Lowe's or Home Depot secured with clothes pins.
Make your own matching shirts before you go. DIS-signs board has some wonderful tips and designs, along with extremely creative and helpful people for those of us who are creatively challenged.
Make a check list of things to do each night for preparation. ie Swap camera battery in charger, lay out clothes, set out mousekeeping tip, refill diaper bag, etc.... It is great to plan to do everything the night before, but sometimes you are just too tired to remember it all.
Check out the Best Park Secrets Thread:
If you look back a few pages you will find these links. They are still active for anyone to download. Have fun!!
Deb- if you do any updates, I can still change the files and repost without a problem.
Here is the link on big paper.
http://jbarnesfamily.com/misc_pics/Best%20Kept%20Secrets_bigpaper.doc
Here is the link for the custom note cards that Deb did.
http://jbarnesfamily.com/misc_pics/Best%20Kept%20Secrets.doc
Enjoy.
I've copied some of these secrets and carried them into the parks. It is fun to surprise your family (and other people around you) with some of this info.