[poundwise]

The advice to keep tires properly is very good. Also, if you maintain your car well, you should expect better gas mileage. Of particular note in this regard is your fuel filter and your oxygen sensor. Check your owner's manual and consider your maintenance histoy to see if you have replaced these items as warranted.

As for driving, the speed you drive is not as important as two other factors; acceleration and stop-and-go. If you punch the gas, or simply accelerate hard, you will burn more fuel. If you have two routes to a destination and one is longer, but straighter and with less stops, you ought to consider that the longer route may be better for fuel economy. Even curves and hills should be considered.

Avoid gimmicks; special vehicle air manipulation devices and so-called 'fuel pills' do not work. Multiple independent authorities have demonstrated this.

The way you drive and the way you plan your trips (as much as in your power), along with maintaining your car, is about the best you can do to save money on gas.

Oh, of course, if you can use public transportation, carpool, or ride a bike, those are alternatives for some people as well.