1.  Avoid High Speeds

As your speed increases, your aerodynamic drag increases in an exponential fashion.  Driving 62 mph vs 75 mph will reduce fuel consumption by about 15%.

2.  Do Not Accelerate or Brake Hard
By anticipating the traffic and applying slow steady acceleration and braking, fuel economy may increase by as much as 20%.

3.  Keep Tires Properly Inflated
Keep tire air pressure at the level recommended by your vehicle manufacturer.  A single tire under inflated by 2 PSI, increases fuel consumption by 1%.

4.  Use A/C Sparingly
When the air conditioner is on it puts extra load on the engine forcing more fuel to be used (by about 20%).  The defrost position on most vehicles also uses the air conditioner.

5.  Keep Windows Closed
Windows open, especially at highway speeds, increase drag and result in decreased fuel economy of up to 10%.

6.  Service Vehicle Regularly
Proper maintenance avoids poor fuel economy related to dirty air filters, old spark plugs or low fluid levels. 

7.  Use Cruise Control
Maintaining a constant speed over long distances often saves gas.

8.  Avoid Heavy Loads
Remove the sand bags from your trunk in the spring and pack lightly for long trips.

9.  Avoid Long Idles
If you anticipate being stopped for more than one-minute, shut off your car.  Restarting the car uses less fuel than letting it idle for this time.

10.  Purchase a Fuel Efficient Vehicle
The higher the MPG, the more money you'll have in your wallet.