Porsche for the 911 gained 10% in town fuel saving by turning off the engine when the vehicle was stopped.
disc type wheelcovers on duals.
windows up and ac on with highway speeds.
55 mph top speed.
keep engine rpm as low as possible at all times. - find and read report by bmw as a result of this study bmw made the bmw 528e e stands for economy.
run the engine as hot as you can and keep the engine in good health. A gasoline engine for racing, I gained 4 hp by running at 210 instead of 200.
The more momentum you conserve the better your fuel mileage.use brakes less.
a gasoline engine the timing curve will have a certain point at each rpm and load that will get you the best fuel efficiency. I would assume a diesel is the same way. Another way to think about this, is to tune the engine for the most efficiency.
The lightest weight oils you can use and still protect parts.
The smallest engine fan you can use and still keep things cool enough.
Run in the wake of a vehicle in front of you.
worn tires get you better mileage, worse for water.
Highway rib tires usually do better mileage than lugged tires.
Well adjusted drum brakes usually do better than well adjusted disc brakes.
IF! shifted well, a manual transmission should net better mileage than an automatic.
An automatic with fluid type torque converter will net better mileage if the torque convert has a "lock up" clutch.
Because most operators do not shift well for fuel savings, the automatics made in the last 20 years, maybe more, usually save more fuel.
tired, that is what comes to mind right now.