1. DIAL DOWN. For every degree you reduce your thermostat setting you may save about 3% on your heating bill.
2. SET THE THERMOSTAT BACK. At night, and when leaving your home unoccupied for a long period of time, set the thermostat back. Note: This suggestion may not be advisable if you have a heat pump system.
3. DON’T BLOCK REGISTERS OR RADIATORS. Keep rugs, furniture or drapes clear of heat registers or radiators.
4. DON’T FULL HEAT UNUSED ROOMS. Close registers or turn off radiators in rooms not being used, and close the doors. Caution: To protect any pipes in these rooms, make sure the temperature is above freezing.
5. CLOSE EXTERIOR DOORS. Keep all exterior doors as well as those to all unheated areas, such as the garage, attic, and basement , tightly closed.
6. USE THE SUNNY SIDE OF THE HOUSE TO BEST ADVANTAGE. Open blinds or drapes to let the sun’s rays in to help warm the house. At night or on cloudy days, close the draperies to prevent heat loss.
7. KEEP YOUR WARM AIR HEATING SYSTEM CLEAN. Clean or replace dirty filters that restrict air flow through your furnace.
8. INSULATE YOUR HOUSE WHERE IT IS NEEDED. Proper insulation will conserve more energy than any other single item. Incrasing insulation levels from a minimal depth to the currently recommended amoount for your area may save up to 30% or more on your heating bill.
9. INSULATE DUCTS AND PIPES. Ducts that carry warm air or pipes that carry heated water to the living areas may go through unheated areas. To increase the efficiency of the heating system, these ducts and pipes should be covered with insulation.
10. WEATHERSTRIP AND CAULK AROUND WINDOWS AND DOORS. Sealing gaps in expterior walls will reduce cold drafts and keep warm air in. It is one of the least expensive ways to save energy.
11. SEAL AGAINST AIR LEAKAGE TO THE ATTIC. Don’t forget to insulate and weatherstrip all attic access doors. Even small cracks around attic entrances can result in substantial heat loss.
12. CLOSE THE FIREPLACE DAMPER OR DOORS WHEN NOT IN USE. An open fireplace allows the heated air in the room to rise up the flue and escape to the outside. Even when a good fire is burning, more heated house air can be drawn into the fireplace and up the chimney than the fireplace can radiate into a room. So use your fireplace prudently.
13. HAVE YOUR HEATING SYSTEM SERVICED BY A LICENSED HVAC PROFESSIONAL. Arguably, the most important tip of all. Whatever the fuel type, have a licensed contractor perform a preventative maintenance system check to ensure your system is operating at peak efficiency and safely.

From Consumer Checkbook email:
https://www.checkbook.org/washington-area/air-conditioning-and-heating-contractors/