In addition to your air conditioning, turn on a fan. By turning on a fan in the room that you are in, you can have your thermostat set one or two degrees higher and not even notice the difference.
Keep your windows, blinds and curtains closed on hot, sunny days to keep your house from heating up. Your air conditioner will have to work a lot harder to lower the temperature if you allow the sun to heat up your house.
If you have an older central air conditioner, consider replacing the outdoor compressor with a modern, high-efficiency unit. Make sure that it is properly matched to the indoor unit.
Don’t place lamps or TVs near your air conditioning thermostat. The heat from these appliances will cause the air conditioner to run longer.
Install white window shades, drapes, or blinds to reflect heat away from the house. Close curtains on south- and west-facing windows during the day.
Plant trees or shrubs to shade air conditioning units, but not block the airflow. A unit operating in the shade uses less electricity.
Caulking and weather stripping will go a long way to helping you keep your air conditioning to yourself. Why waste it!