On long drives, use the cruise control to save gas. The gradual acceleration and deceleration improves your fuel efficiency.
Putting luggage and other items on top of your vehicle creates drag. To reduce these effects, put the luggage and any other items inside a roof top container or wrap them in a tarp secured by a rope.
This not only causes less drag, but also protects your items from weather.
You don’t need to warm up your car in the morning—that’s an old myth. As long as you are not subjecting the car to excessive loads right away, driving your car under normal conditions will naturally bring the car to optimum operating temperature. Idle warm−up periods waste fuel and cause air pollution.
Keep your tires properly inflated to keep your gas mileage high. Driving with low tire pressure is like riding a bike with a flat. Besides wearing down your tires, it simply wastes energy. Proper inflation levels are determined by the manufacturer, but are usually about 32 psi.