These days it seems more common to overhear comments about a particular car's appalling fuel economy than idle chatter about the weather, which makes sense when a gallon of gas costs as much as a cheap umbrella. For instance, just the other day there was some guy going on about how his car was getting 3 mpg less than just a few months ago and had no idea why. That is until it was pointed out to him that his car's adjustable luggage rack was in its full, upright position, giving his car the aerodynamic efficiency of a cinder block.

That's just one of the points Forbes includes on its list of things to do so you can drive green without buying a new car. Improving your gas-guzzling vehicle's sleekness by losing that luggage rack, ditching that inefficient and egregiously ugly three-foot-tall spoiler and quit sticking your hand out the window are all little things that add up to an appreciable difference at the pump.

Most of the advice is common sense we've all heard before, but Sebastian Blanco, editor of AutoblogGreen, offered a novel suggestion for the list. Reduce your car's weight by only filling up half the tank. One gallon of gasoline can weigh as much as 6.5 lbs. On a 2008 Ford Escape, a half a tank of gas weighs 53 pounds.

Like the Forbes article points out, there's only so much you can do to curb a car's drinking habit, especially if you're driving something like an Escalade. But in smaller, lighter cars, even small steps like this can make a big difference in your fuel bill.

[Source: Forbes.com]