Clean filters once a month.
Check the filters monthly and replace them if they're dirty.
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.
Got them in the bathroom and kitchen? Use them. They remove heat and moisture.
Close them during the day, especially on the east and west sides of your home.
Close them during the hottest hours every day. At night, open window opposite one another for cross ventilation.