A couple more tips to add to the list:

[fowljesse]

I was just thinking about stuff I do to save gas that I don't even think about anymore. They aren't for everyone, but, if you have a manual transmission, and park somewhere steep enough (like I do), you can let the car roll, and start the car by turning the key to "On", but not "Start", and let out the clutch, so the wheels start the car, and not your battery. This way, the alternater doesn't have to engage, and make up for the loss.

Also, my car had all filament bulbs until I changed everything (outside, and inside) over to LED, to save the alternator work a little more. You can go to many sites, and type in your bulb number to get the LED equivilent. My car didn't have projector headlights, so I had some made, and put them in. If your car doesn't have projectors, and you can find atermarket ones, you'll probably have brighter headlights, and use less energy by putting them in. Having brighter headlights can also save you gas by allowing you to drive more confidently at night, maintaining an efficient speed.