13. Optimize your route.
The less distance you drive, the less gas you use. If you have several stops to make, see how you can route your trip to have the minimum number of miles driven. Keep an eye out for traffic jams, however – often you are better off driving more miles (sometimes even several dozens of miles) than sitting in traffic jams.
14. Consider walking or using a bicycle for short trips,
or use public transportation if convenient and cost effective. Yes, you actually save gas (and money) when you are not using your car.
15. Consider carpooling if possible.
Sure, it's inconvenient sometimes, but it's the single most efficient way to save money on your daily commute.
16. Get a credit card with 5% rebates on gas,
use it for all your fuel purchases and guarantee yourself an automatic 5% savings.