1. Avoid High Speeds
As your speed increases, your aerodynamic drag increases in an exponential fashion. Driving 62 mph (100 km/h) vs 75 mph (120 km/h) 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. Service Vehicle Regularly
Proper maintenance avoids poor fuel economy related to dirty air filters, old spark plugs or low fluid levels.
5. Avoid Long Idles
If you anticipate being stopped for more than 1 minute, shut off the car. Restarting the car uses less fuel than letting it idle for this time.
6. Purchase a Fuel Efficient Vehicle
When buying a new vehicle examine the vehicle's rated fuel efficiency. Usually choosing a small vehicle with a manual transmission will provide you with great fuel economy.
If you really want to save on gas consider using public transportation, bike, or walk!