Insulate and Ventilate Your Home
One way to save money on cooling costs is to not operate an air conditioner when you can get by with outside air. If your home is well insulated, that will help keep unwanted heat out. Keep windows shaded and curtains closed during times of the day when the sun would pour into unprotected windows. Keep the production of heat in the home to a minimum by grilling outdoors and using microwave ovens rather than heating an entire oven in the kitchen. Use bathroom ventilation fans to remove warm, moist air during showers. And replace incandescent lamps with energy efficient compact fluorescent ones, which produce a quarter as much heat as incandescent lighting.
Then, open the windows and enjoy natural ventilation if the breeze is blowing, or turn on a fan. Fans use a small fraction of the energy required to operate the air conditioner. Window or whole-house fans can be used to bring in outside air when it's cool enough to do that, and ceiling or portable fans can stir the air so you'll feel cooler at higher temperatures. Fans can do that because as they increase air flow across your skin, they increase evaporation of the skin's moisture, which makes you feel cooler.