wikiHOW has 18 recommendations, tips and warnings to show you How to Save Money on Gas. My favorites:
6. Turn off the AC. Running your car’s air conditioning puts extra strain on your car’s engine. This translates into your car eating up more gas per mile. Use less gas, save money. Depending on the car you drive, at highway speeds, the AC might put less drag on the car than if all the windows are open. So, you might want to keep it cool on the highway.
18. Avoid having to stop. If approaching a red light, see if you can slow down enough to avoid having to actually stop (because you reach the light after it is green). Speeding up from 5 or 10 miles per hour will be easier on the gas than starting from full stop.
Special thanks to Lifehacker for pointing me to this list.