And with winter upon us, there's no better time to start. Also avoid heat vents. Make sure the machine is level, and that the area around the grill and any vents is both clean and unblocked. A good cleaning once a year will increase both efficiency and life. Wipe moisture from containers and cover liquids.
Excess humidity makes the compressor run longer.
Freezers that are at least two-thirds full run more efficiently. If near-empty, reuse and fill plastic milk jugs with water and place inside. These use far less water. If available, use the no-heat fan or air dry setting. Don't bother pre-rinsing dishes that contain only a normal amount of residue.