Protect your pipes
Winterize outside faucets. Disconnect all garden hoses and wrap all outdoor faucets with rags, newspaper or insulating material. Cover the wrap with plastic or other material to keep moisture from getting inside.
Cover foundation vent holes to keep your crawl space warmer. Remember to uncover these vents when the winter freeze is over.
Insulate any exposed pipe. Use heat tape if necessary.
Keep a trickle of water running from your indoor faucets during prolonged freezing spells. A small trickle of water will cost you a few extra cents a day but save you the cost of repairing frozen pipes and dealing with water damage.
Keep cabinet doors below sinks open so that the warm interior air can get to your pipes and drains.
Protect your water heater. If you are without water (because of frozen pipes or other reasons) be sure to turn off your hot water heater to prevent damage to it. Also turn off the breaker to the water heater.
Weatherize in-ground irrigation systems. Be sure to annually winterize your in-ground irrigation or sprinkler system so you won't have broken pipes in the spring when you turn it on.
If you're leaving home for a few days, keep your heating system turned on to a low temperature so that some heat is available to keep pipes from freezing.
If you leave home for the winter, turn off the main shut-off valve to your water supply and drain your faucets. Some homes with basements have separate shut-off valves for each outdoor faucet, in addition to the home's main supply valve.