Turn off the lights when you leave a room.
Don't let the water run when you wash the dishes, brush your teeth, or do other chores.
Plan meals so that you can bake more than one item at a time.
Don't use major appliances or bake during the hottest part of the day (if it is summer time).
Don't leave windows and doors open if the heater or air conditioner is running.
Make sure the refrigerator door closes all the way.
Wear a sweater in the winter time instead of turning up the heat.
Don't keep the thermostat too high in the winter or too low in the summer. Energy experts suggest that you keep the thermostat around 78 degrees in the summer and 72 degrees in the cooler months. Unless your house is heated and cooled with a heat pump, you can also adjust the thermostat to provide less heating or cooling when you are not home (or when you are sleeping).
Install storm windows and storm doors with screens for spring and summer use. Storm doors and windows can reduce energy usage.
Put a special insulated "blanket" around your hot water heater. Set the heater at the lowest setting. Insulating your water heater can prevent heat loss and reduce operating time.
Install attic fans or vents to keep hot or cold air from being trapped in your attic.
If you need to buy new appliances, get the most energy efficient ones you can afford.
Install ceiling fans.
Monitor your heating and cooling systems. Be sure to replace the filters on units often to keep adequate and clean air flow. This will reduce energy costs. Keep registers and vents free of dust, dirt and other blockages. If you have rooms that are not used often, keep their registers and doors closed. Cover or remove window air conditioners during winter months to prevent heat loss.