Most microwaves can only penetrate food that is an inch thick or less. So, always make sure that the foods you are cooking in the microwave are cut into pieces that are an inch thick or less. Cooking larger items is possible, but the inside of food only gets cooked by the heat radiated inward from the outside of the food. In foods that are more than an inch thick, this process is very inefficient and slow.
Microwaves tend to heat the outside edges of a plate of food first, often leaving the food in the center of the plate cold. When you're heating up leftovers, leave the center of the plate empty and line your food items around the edges. Your food will heat more evenly.
Salt attracts microwaves, so if your food has a fine layer of salt on top of it, the upper part of the food will get dried out as it's cooked or warmed up. If you like your foods salty, add the salt after you heat the food in the microwave or make sure that the salt is mixed in.
You don't need a steamer. You can steam veggies and other foods in the microwave. Simply cut them up to less than an inch thick, put them in a ceramic bowl, add 2 to 3 tablespoons of water and place a ceramic plate over the top of the bowl like a lid. Microwave on high for 3 to 4 minutes.
Not sure if your bowls or plates are microwave safe? Michigan State University says that you can find out with a simple test. Place the empty container inside the microwave, place another container inside of the microwave and pour 1 cup of water into the second container. Heat them on high for one minute. If the empty container is cool it is microwave safe, but if it is slightly warm, you should only use it when reheating foods, not for cooking. If the container is hot it's not microwave safe.
The American Chemistry Counsel suggests only using round or oval shaped bowls. Round or oval heats food more evenly than square or rectangular shaped containers because corners receive more energy. This can cause food in the corners of the bowl to heat faster than the rest of the rood.
Every microwave has areas where food will heat faster. To find your microwave's hot spots, place a plate covered in marshmallows into your microwave for 50 seconds. The area of marshmallows that puffs first are in the hot spots. Next time you warm up a plate of food, scooch it over to a hot spot for faster heating.
Plastic can absorb odors, so you may find that your microwave has a tendency to smell from time to time. Bad smells can even make the food you put in the microwave taste different. To get rid of stink, mix 1 to 2 cups of water with ½ cup lemon juice in a small container, cover lightly with a cotton cloth and heat in the microwave on high for approximately 5 minutes. You may need to repeat the heating process a couple of times for strong odors.