Be oven-wise. Stop opening it to check food. Heat escapes, wastes energy and slows down cooking. Switch it off before your meal is ready. The temperature in the oven would still be hot enough to finish cooking the food.
Put a lid on it. Saucepans, I mean. It’ll heat the food quicker and you’ll use less energy.
Cool it off. Hot or warm food straight into the fridge makes your refrigerator exert more energy. Let it cool first.
Let ’em steam. Use your steamer wisely. Most steamers have removable bases. You can cook various food items in each base. All in one take.
Chill out. Defrost your fridge regularly to keep it running efficiently and cheaply.
Eat more veggies. Produce is cheaper energy-wise than raising animals.
Use a toaster, not the grill. It uses less energy.