When not in a traffic lane, turn off your car engine if stopping for more than 30 seconds. Restarting uses less gasoline. If you're driving on the freeway, keep your windows rolled up. Opening a window creates wind drag and will lower your mileage. Instead, use the car's flow-through ventilation.
Fuel economy decreases as speeds go up.
The choice you make in engine oil can also effect fuel economy. Your owner's manual will recommend the type of oil to use under specific conditions. Make sure that all used oil is taken to an oil-recycling center. Luggage racks increase vehicle drag, and too much weight in the trunk can cut your mileage. On the average, each 100 pounds of needless weight will cost up to one-half mile per gallon.