Keep extra batteries for flashlights and radios and maintain an ample supply of food which requires no cooking or refrigeration in the event of power failures.
Have alternate water supply in case water pipes freeze. Make sure all exposed water pipes are well insulated. (Home Depot and Lowe's carry materials for this.) The water pipes may freeze and break, causing serious water damage to the home. Check with your local utility company as to the safest way to leave your gas supply and whether you should drain your water pipes, or leave a tap running. Prepare your home in advance if you are going to be away during a potential hard freeze.
Be sure to have an adequate supply of warm clothing and bedding for each member of your family.
Use emergency cooking and heating facilities very carefully and only in well-vented areas.
Have your car checked and winterized early in the season.