Lower your temperature down by 1 to 2 degrees in the winter and raise it 1 to 2 degrees in the summer months. (especially at night when you are sleeping)
2. Don't run your heat as high or your cooling system as low whenever nobody is at home.
3. Make sure all air filters are clean, all year long.
4. Heat/cool only rooms that you are using. Close the vents and doors to unused rooms/
5. Install storm windows or install inexpensive plastic sheeting on the inside to control temperature efficiency (especially in winter)
6. Make sure all your doors and windows are sealed with weather stripping strips and or sealants, such as caulking.
7. On a windy day feel for leaks around windows and doors, make sure you get them all sealed as quickly as possible.