how to use less fuel in your car

Apply parking brake,
Put car into neutral/park,
Switch off the engine,
Lock the car.
Walk away.

Even better, fail to apply the parking brake......

Tips for better situation awarenes in the sky: mandatory ADSB-OUT, cheap ADSB-IN display - but Dick won't like that.

I don't start the engine. Since I began doing that, my fuel usage has dropped to zero! Unfortunately, this has also caused the odometer to fail.