Don't open the door till you know what you want. Make sure your refrigerator and freezer doors are air tight. Adjust the door or replace the gaskets if necessary. Lubricate the gaskets with petroleum jelly to keep them from cracking or drying out. Vacuum the condenser coils in the back or bottom of refrigerators and freezers.
Dust causes the unit to run more.
If you're going on vacation, remove perishables from the refrigerator and turn the setting up a few degrees. Don't put uncovered liquids in the refrigerator. It will work harder to remove the moisture. Let food cool slightly before putting it in the refrigerator. Put your refrigerator and freezer away from direct sunlight and heat-producing appliances such as stove, water heater, dishwasher, washing machine or clothes dryer.