I eat a lot of leftovers, but at times some meals taste better than others after a day. The trick I have found to making the ones that fall flat after 24-hours of rest is to re-season them. Normally, another dash of salt or pepper will bring the dish back to life. What's your secret for reviving leftovers?
Tupperware literally changed my life once I bought a whole set. Kept all my food fresh and basically tasting the same the next day. While putting a cover over a bowl or dish is a decent option, it simply doesn't compare to putting your leftover food in tupperware.
I simply use the left-over food as an ingredient for another meal I'm making. That way, I not only get a fresh meal but I avoid wasting food. p.s I normally don't cook too much food so it's only occasionally that I have leftovers.
I rarely have left-over food. Occasionally I cook a big pot of grains or beans that will last me a for a couple of days in the fridge. I only do it because the soaking and preparation of certain beans, such as aduki beans, takes at least 24 hours. But if there are some left-overs, I tend to make a good sauce or dressing and add some fresh food to it, to turn it into a satisfying experience.
Seasoning is your friend. I will either reheat it on the stove or the oven, it helps a lot than just nuking it in the microwave. Also, depending on what it is, adding a little oil, milk, or butter, to things like pasta or casseroles really pick it up. Not to mention I will add salt, pepper, and a hint of garlic or onion, or another flavor to change it up and make it taste like new.
I usually re-season it only if necessary, but I usually don't think leftovers taste so horrible compared to cooked fresh where I can't still eat it. If I have to, I will put it back on the stove and throw other things in it to make a whole new dish. That usually works for me!
Preservation is key. Pack it up well and refrigerate as soon as possible. Also, the reheating (if necessary) method is key and depends on the type of food. Use a toaster oven as opposed to a microwave if you want to avoid certain foods getting soggy such as pastries and pizza. That's where my experience ends as my most frequently eaten leftover food is pizza. Sometimes it tastes even better than it originally did to me.