Set your thermostat between 65* and 68*F and your nighttime temperature at a lower setting. For each degree you lower the thermostat you can save about 1% on your gas bill.
Regular change or clean air filters as required. Heating units use less energy and work more efficiently when filters are not clogged or dirty.
To prolong the life of your furnace and decrease energy usage, have your furnace checked by a licensed contractor