Fit pans to burner size and use as little water as possible when cooking with them. When preparing a dish which can be cooked either on top of the stove or in the oven, always choose the top of the stove. Burners, both gas and electric use less fuel than ovens. Make sure that gas pilot lights are adjusted property and that electric elements and switches are in good working condition. Replace worn out oven door gaskets.
Deteriorated gaskets are an expensive way to heat a kitchen.
Always use your appliances as efficiently as possible. Keep them in good repair and clean, with worn parts replaced. Read and follow the manufacturer's instructions for the proper use, cleaning, lubrication and other maintenance of all your appliances. And do with appliances as you do with incandescent lights, turn them off when they're not need.