6. Track miles per gallon: Calculate your gas mileage on a regular basis. The easiest way to do this is start with a full tank and reset your trip odometer. At your next fill-up, divide the number of miles driven by the number of gallons it took to refill the tank.

7. No junk in the trunk: The additional weight you carry in your vehicle doesn't ride for free. It takes energy to move it around. Removing unnecessary stuff from your vehicle saves fuel.

8. Sack the racks: If you have a roof or bicycle rack and you don't use it, remove it. They create aerodynamic drag, resulting in decreased fuel economy.

9. Go with the flow: Traveling at a constant speed on a highway in a flow of traffic is more aerodynamically efficient than going the same speed in isolation. A uniform flow of traffic generates a wind current you can benefit from.

10. Timely fill-ups: Plan to refuel your car during off-peak times to avoid lines and excessive idling.

11. Path of least resistance: On a super highway, choose the more open lanes and keep a cushion of air around you to avoid unnecessary and unpredictable braking/changes in speed. In a more urban setting, avoid bus lanes and lanes from which cars are turning into driveways and parking lots.

12. No sun, no moon: Keep the roofs closed at higher speeds. Some sunroof styles are better than others. The worst offenders are the kind which tilt and slide to the outside, on top of the roof. When open, these "roof-top spoilers" can significantly increase aerodynamic drag.

13. Drive shoeless: Some hardcore hypermilers drive in socks or bare feet so they can modulate the accelerator to the finest degree. It shouldn't be that surprising. Race car drivers typically wear extremely thin-soled boots for similar reasons: for the highest level of tactile feedback from the vehicle, and to better finesse the pedals.

14. Avoid parallel parking: For on-street parking use pull-in, pull-out spots rather than spots that require multiple reverse and forward maneuvering. Pull-through spots are even better -- they avoid burning gas to go in reverse.

15. Pick the periphery: Choosing a spot at the outside edges of a busy lot is far more efficient than driving around trying to get as close as possible to the building or destination.