Kids meals, and you don't have to get what automatically comes with the order. If you don't like something or aren't going to eat it, then ask for it without, and it will save you a little bit.
I also love to splurge on treats in the park. I don't salivate over Disney's burgers and fries, but some days, I just want that Mickey's ears ice cream pop or a Tigger Tail or a Dole Whip. Having a treat in the park feels special and exciting because I can't get it elsewhere, and then I do not feel so deprived pulling out sandwich for lunch.
Sometimes I don't want to bother carrying things in the parks, so meals in the parks is WAY more convenient. In these cases, split an adult meal and then split a treat. Drink water.
But the best way for me to save are with Disney Gift Cards. There are all sorts of ways to save on those... 5% with Target Redcard, Fuelperks bonuses, or my grocery store did $10 in store coupon for anything with $50 Disney giftcard purchase. Instant 20% off meals was way better than an extra bun!