Frozen wash cloths. I bought an insulated lunch sack at Dollar Tree to carry them in, to keep them colder longer. I simply soak washcloths (folded in quarters) in the evening, put them in sandwich-sized zip locks, and freeze overnight. Pop them in the insulated lunch sack, then into the backpack. They feel so darned good on your arms, neck, face in the middle of the afternoon!
Frozen water bottles. Fill your water bottles (the regular kind you get in the grocery store- AquaFina, Poland Springs, whatever) about 1/3 full and freeze overnight. Top up with fresh cold water in the morning and stick them in the backpack. They'll stay pretty cold for a long time.
If you don't want to carry water bottles, take advantage of being able to get ice water for free from all QS restaurants.
We bring powdered drink sticks- the little tubes that have instant tea, drink powder, whatever- or MiO drops as we find there's only just so much water we can drink before feeling gross. Somehow the flavors make it easier to get the water down.
Walk in the air-conditioned shops. They interconnect along the main streets/walking areas. Take advantage of these small shots of air conditioning!
SHOWS. These are known as "the rides where you sit down in a/c" in my family. Twenty minutes sitting in dark, air-conditioned bliss? DO IT.
I'm not saying it's for everyone, but we don't rope drop. We sleep in, swim a bit, relax, and get to the parks around 11am. We do some rides, have some lunch, do some more rides, have a TS dinner around 7-ish, then stay until the parks close. We tried doing rope drop one trip, then back to the resort for lunch and a swim. UGH. It was us and 2 billion of our closest friends in the pool, which was warmer than the ambient temperature and not at all refreshing. We really are night-park people; we always choose the park that is open latest, and stay as long as we can. Can't be at Epcot at 8am if we were still in MK at 1am! It works for us.
TMI time. You are going to sweat, and be wet to the skin. Your undies are going to be wet all the time, from the sweat. Please bring a second set of clothes for each day, or be prepared to do laundry mid-trip. If you go back to your hotel for a break at any point, you are going to want to change your clothes. If you go swimming, you are not going to want to crawl back into icky, wet, sweaty clothes. Trust me on this.
We spray our feet with antiperspirant deodorant every morning. It cuts down on foot-sweat, which cuts down on chafing and blisters.
I have these fans that hang around my neck. They are shaped like iPods, only big, and are battery operated. The fan hangs around your neck and blows air upward onto your neck and face. They are pretty sweet. I got them at
Walmart.
If you take an umbrella, please, please, PLEASE be aware of other people around you.