All of these tips and more can be found at http://www.howtoadvice.com/savinggas. This was a great article, but the general advice section was the best part. Here are tips number 16-30
16. Do not rest left foot on floor board pedals while driving. The slightest pressure puts "mechanical drag" on components, wearing them down prematurely. This "dragging" also demands additional fuel usage.
17. Avoid rough roads whenever possible, because dirt or gravel rob you of up to 30% of your gas mileage.
18. Use alternate roads when safer, shorter, straighter. Compare traveling distance differences - remember that corners, curves and lane jumping requires extra gas. The shortest distance between two points is always straight.
19. Stoplights are usually timed for your motoring advantage. By traveling steadily at the legal speed limit you boost your chances of having the "green light" all the way.
20. Automatic transmissions should be allowed to cool down when your car is idling at a standstill, e.g. railroad crossings, long traffic lights, etc. Place gear into neutral position. This reduces transmission strain and allows transmission to cool.
21. Park car so that you can later begin to travel in forward gear; avoid reverse gear maneuvers to save gas.
22. Regular tune-ups ensure best economy; check owner's manual for recommended maintenance intervals. Special attention should be given to maintaining clean air filters... diminished air flow increases gas waste.
23. Inspect suspension and chassis parts for occasional misalignment. Bent wheels, axles, bad shocks, broken springs, etc. create engine drag and are unsafe at high traveling speeds.
24. Remove snow tires during good weather seasons; traveling on deep tire tread really robs fuel!
25. Inflate all tires to maximum limit. Each tire should be periodically spun, balanced and checked for out-of-round. When shopping for new tires, get large diameter tires for rear wheels. Radial designs are the recognized fuel-savers; check manufacturer's specifications for maximum tire pressures.
26. Remove vinyl tops - they cause air drag. Rough surfaces disturb otherwise smooth air flow around a car's body. Bear in mind when buying new cars that a fancy sun roof helps disturb smooth air flow (and mileage).
27. Auto air conditioners can reduce fuel economy by 10% to 20%. Heater fan, power windows and seats increase engine load; the more load on your engine, the less miles per gallon.
28. Remove excess weight from trunk or inside of car - extra tires, back seats, unnecessary heavy parts. Extra weight reduces mileage, especially when driving up inclines.
29. Car pools reduce travel monotony and gas expense - all riders chip in to help you buy. Conversation helps to keep the driver alert. Pooling also reduces traffic congestion, gives the driver easier maneuverability and greater "steady speed" economy. For best results, distribute passenger weight evenly throughout car.
30. During cold weather watch for icicles frozen to car frame. Up to 100 lbs. can be quickly accumulated! Unremoved snow and ice cause tremendous wind resistance. Warm water thrown on (or hosed on) will eliminate it fast.
Posted by Sidney Mitchell