Depends on the reasons for trimming (i.e. avoid unnecessary spending, avoid overpriced $2 snacks, needing to cut the budget....)
So take or ignore whichever tips you like--but we have been successful with all of these:
1. Take snacks--Bringing a box of nutrigrain bars will be cheaper than anything on site...worried that you can't have your rice crispy treat? Bring a box or make your own and hand cut out the mickeys if you need to. I find snacks to be the #1 budget waster for us, so this is usually our first trim. We will budget in a Mickey bar, but as a whole--we don't want to be dollared and fived to death on snack food. We usually like to bring larabars as they are high in protein, yummy (to us) and hold up well in all kinds of weather (no melting as long as you don't get the chocolate ones). The Mickey bar, dole whip, kitchen sink kind of treats are limited to once or twice per trip (depending on length of the trip) per person. We consider that an edible souvenir.
2. Cut breakfast--I can't recall the last time we ate breakfast at Disney unless it is a big to do. I have the same issue at home--going out to spend lots of money on a breakfast when simple will do. We pretty much always do our own breakfasts. We are a family that can do simple breakfasts. Having a kitchen, you can still do the eggs, bacon and pancakes if that floats your boat. But we just hit one food court too many for a $50 breakfast a few years ago and cried uncle.
That leaves...lunch and dinner....
3. For sitdown--if you are hankering to eat at a sitdown establishment at Disney, lunchtime is THE time to do it. You will save probably several dollars per person. You can even cheat it and make it a late lunch (I think you can get seated until 3pm in most places), then it almost counts as dinner.
4. If you have kids--ditch the kids meals and have them share and adult platter at counter service. I think it comes out cheaper.
5. Drink water.
6. Now that I mention water, we usually freeze a bottle and that kind of helps the other bottles that we bring along somewhat cold for the day. If it is summer, we freeze more. It is a bit heavy, but we are still toting strollers, so into the bottom of the stroller it goals. We likely would ditch that once we no longer have strollers...b/c it gets heavy to lug all that water and ice. We aren't afraid to share bottles either, so in the times we have to buy one--we share. For those that don't, water is free in every single restaurant and counter service.
7. pack your lunch...we did this for quite a bit with our young ones. It requires a sturdy portable cooler that is lightweight but won't cause things to get squished.
8. The last tip--have dinner in your room that you cook. Now it can be something simple or something extraordinary--but whatever it is, it will be much less expensive than what you can buy on site.
That being said, it is a vacation. We do not use all these tips all of the time (except breakfast and snacks pretty much). Who wants to cook all the time? You take the tips that work for you and ditch the others.
If you don't want to slave over a hot stove, then don't. Sharing meals and drinking only water can help stretch the pennies for the meals you do dine out with.
If we have a buffet scheduled on a day--we pretty much do not have a second meal out, unless it is breakfast and then we might have a late dinner. By "we", I mean the adults. While we do not gorge ourselves, we do eat a reasonable amount of food that keeps us stuffed. Our kids stop eating once their tummies tell them to, so we will usually buy them a snack type dinner. In July, we had CRT for lunch...so for dinner, we had snacks from Casey's for dinner while waiting for the parade (nachos is what I remember).
That is what we do and it works for us. YMMV.
Have fun planning!
(ps we did
DDP once and while that was lovely--we realized that we don't like eating out all of the time every single day of the trip. It is nice to be able to choose not to eat out.)