Remember when SUVs began taking over the roads in the 1990s and drivers of the heavy gas-guzzlers felt like masters of the universe? With fuel prices being what they are today, the hybrid owners are the envy of all. You've spent hours researching how to save money on your personal or business auto insurance; now, how can you further reduce your driving costs even if you can't afford to buy a more fuel-efficient vehicle?

Take heart. There are many ways to decrease your fuel consumption that don't require buying a new car. The catch? You'll have to make some changes to both your style of driving and living.

According to Philip Reed, Senior Consumer Advice Editor at Edmunds.com, where the most common tips on how to be a fuel-efficient driver were road tested in 2005 and again in 2008, there are more miles per gallon to be had—as high as 38 percent more, depending on the vehicle—awaiting those who can change from "aggressive" to "calm" drivers.

"We're seasoned car guys and we were pretty surprised at the results we got. If we were surprised, we think others will be surprised," said Reed.

Calm driving means setting the cruise control to 65 mph on a long trip. It also means not being in such a hurry to get from 0-60 miles per hour when the light turns green. Adding just five more seconds to your pace of acceleration saves fuel. So does driving the speed limit, maintaining a constant speed and braking gradually instead of abruptly. Of course, your blood pressure might go up when the speeders begin tailgating and honking and waving their fists at you. Try getting a bumper sticker that says, "I'm saving ga$ by driving the speed limit." If that doesn't start a trend, just stay in the slow lane.

As for the "A/C or windows down?" debate, it depends on the vehicle. Windows down can create aerodynamic drag on some cars, while running the A/C increases fuel consumption by about one or two percent by putting extra load on the engine. Other aerodynamic causes of decreased mileage include heavy items in the trunk or truck bed and luggage tied to a roof rack.

Finally, all the experts advise against idling for more than a minute. If you're waiting for your kids, your hamburger, or your deposit receipt, turn off the engine.

Says Reed, "In the old days, with some of the cars I drove, I worried about the car not starting again if I turned it off, especially in winter. But with fuel injection, which replaced carburetors, they start well now."

It's important to change more than your driving in order to maximize the savings. Ask yourself, "Do I have to do that errand right now?" If you wait until three or four things pile up and map out the shortest route, you'll save money. For trips close to home, consider walking or riding your bike. Even better, get acquainted with your city's public transportation system and begin carpooling with friends when all of you share the same destination, such as the supermarket.

And don't forget maintenance. Reed says the two most important items for good fuel economy are proper tire pressure at all times and changing the air filter to get a good fuel flow. The better your car runs, the less chance you'll waste gas and money.