Miserly /6

Cool air is a must, gas is much more efficient when mixed with 80 degree air then 200 ..no more tread on the ground then you need, and keep everything smooth bearings not to tight but still safe and secure will move very easy.
I have seen small cars or what ever on a level slab of pavement and if it was in neutral it was hard to push and would not keep rolling, that will eat up gas milage.