you can start at the pump.
1. pump the gas very slow, if you can smell it, you are losing money. gas is a vapor!
2. gas is heavier when it is cold, so best to get gas when it is late in the evening or early in the morning.
3. try to refuel before tank is below half.
4. never refuel when a tanker is delivering the fuel to the stores.
i have also heard that every car is designed to operate half gas, half grain alcohol. so having an apple tree and a 'still' wouldn't be a bad idea. that's how the farmers still do it where i grew up.
thanks for the heads up on adding more air pressure to the tires.