Use compact fluorescent lamps. You can lower your lighting bill by converting to energy-efficient low-wattage compact fluorescent lighting and fixtures.
Weather-strip around window and doors.
Fix defective plumbing or dripping faucets. A single dripping hot water faucet can waste 212 gallons of water a month. That not only increases water bills, but also increases the gas or electric bill for heating the water.
Set thermostats at 78 degrees F for cooling in the summer and 68 degrees F for heating in the winter; this will save 10-20 percent of cooling costs and 5-20 percent of heating costs.