2. Turn off lights, computers and appliances. This simple habit doesn't cost a dime and could make a big difference in your energy consumption, depending on how consistent you are. Teach children and other members of the household to follow this rule: If no one's in the room, it doesn't need to be on. In other words, shut off TVs, computers and lights before leaving a room, every single time. It's a habit that requires a bit of diligence in the beginning but will soon become second nature.