Air Conditioners
Clean filters once a month.
Central Air
Check the filters monthly and replace them if they're dirty.
Ceiling Fans
Use them to reduce cooling costs. A ceiling fan with the air conditioner on low will provide the same comfort as an air conditioner set to high, and will save money.
Exhaust Fans
Got them in the bathroom and kitchen? Use them. They remove heat and moisture.
Shades
Close them during the day, especially on the east and west sides of your home.
Windows
Close them during the hottest hours every day. At night, open window opposite one another for cross ventilation.