Answers.com has some great tips on how to make those leftovers you have taste great when you reheat them!
Add More Liquid
When you are reheating pastas, soup, mashed potatoes, or anything you used liquid to make, add some extra liquid before you reheat it. Mac and cheese might require a little milk while plain pasta can be reheated with water or your favorite broth flavor. Liquid adds extra flavor, plus it makes the food moist and delicious.
Use a Damp Paper Towel
If you find yourself craving last night’s pizza, don’t throw it in the microwave all alone. Dampen a couple pieces of paper towel and wrap the pizza in it for about 45 seconds. The moist paper towel will help make the pizza softer, and you won’t have to worry about your pizza coming out hard as a rock.
Use a Resealable Bag
Resealable plastic bags aren’t just for storing leftovers, they are great for bringing them back to life, too. You can grab leftover meats and throw them in a bag with your favorite vegetables with a tiny bit of water, seal the bag, and stick in the microwave. Heating times will vary depending on the type of microwave you own. The result is juicy meat and fresh steamed veggies.
Use a Steamer Basket
Foods like chicken, turkey, and seafood can end up getting tough if they are kept as leftovers. A neat way to reduce the toughness and make them taste fresh again is to use your steamer basket. Fill your saucepan up with water as you normally would to steam veggies, but instead throw your poultry or seafood in the basket instead. You’ll find that the food tastes as though you just made it.
Slice it Up
If you have a big cut of meat to reheat, consider slicing it or dicing it up. Put your cut up meat in a microwave safe bowl into the microwave. After a few seconds, you’ll have some delicious meat you can eat the way it is, or add to other dishes.
Use a Skillet
The microwave is your best friend when you need to reheat leftovers, but sometimes foods come out tasting stale, hard, or rubbery. To avoid that, use your skillet. Place your leftovers, a small bit of liquid or butter, and a little extra seasoning into the skillet, and you’ll end up with a delicious new twist to last night’s dinner.
Warm up in the Oven
Turning your oven on warm and putting your leftovers inside, is one of the best ways to reheat your leftovers. The warm setting allows your food to heat more evenly, and you can keep it from overcooking.
Just because you made a roast beef and potatoes last night, doesn’t mean you have to have that exact dish for lunch or dinner the next day. Take your leftovers and create a whole new dish. Leftover roast beef is great for shredded beef tacos, sandwiches, and salads. Chicken can be shredded for soups and other great dishes. A little creativity can help you repurpose your leftovers and save you money on another meal.
If you are in a hurry and don’t have time to use your skillet or oven, a bowl of water is your best friend. After you put your leftovers in the microwave, stick a bowl of water in beside the dish being reheated. This will create moisture inside the microwave, which will make your food moist and delicious.