Yesterday, when I got up, I had to run a few errands. This meant getting in my car.
I turned the key. Nothing happened. I already knew what was wrong, so I got out and wiggled the wires connecting the battery to the rest of the car.
The hood light came on and I knew I was back in business. There is a lot of good information about cars at this site.
The battery gets charged by the alternator. Because I have corrosion at my terminals, it takes my car more time and more gas to get my battery charged back up. (And yes, I am going to clean those pesky terminals today.) All of the electricity in the car comes from the gas tank, so to save gas reduce the energy you use in your car.
Do you need to have the fan running in the back seat when you are driving alone?
How much suffering would it be to run the AC a little warmer or the heat a little cooler?
Do you really need the heated seat?
Sometime I think that we would drive a lot less if it were a little less comfortable. And that by itself may be enough to use less gas. Since the only way to really use less gas is to drive less.