Snacks - take little things with you, crisps, biscuits etc. Snacks and drinks are super expensive, think $5-7 for popcorn or a little tub of crackers. Ice lolly’s similar so if you can keep costs down by taking little bits and pieces it saves a fortune.
As above - drinks, take water bottles with you so you can fill up with iced water which restaurants/quick service will give you for free. We take those mini Robinson Squeezy juice for those who don’t like plain water. A 500ml bottle of coke etc is $5 in the parks. If you are staying on Disney property definitely get a refillable mug, they are about $22 but you can use them as much as you want at your resort.
We also get an Uber to a Walmart to pick up drinks, snacks etc.
Cooling towels/portable fans, get them before you go, they are very expensive there. Like $30 for a fan kind of expensive!
Make the effort to get up and get to the parks early, especially if you are staying on site and you get early entry. You can get so much done and then have a break during the afternoon when it gets really hot.
If you are thinking of using genie+ I would prioritise magic kingdom and Hollywood studios with this - I don’t think it’s worth the money at Epcot and animal kingdom because they don’t have as many rides, especially if you can use early entry.
Work out which rides get busiest and speed walk to those as soon as they open the parks, if you miss this time then wait until later in the day. You can get in a queue until a minute before park closing time, ride times will still post long queue times to put you off but you will find them much lower than advertised.
As you can probably tell, we go every year pretty much so ask away if you need anymore tips!