One of the best ways to save gas is to simply reduce your speed. As speed increases, fuel economy decreases exponentially. If you one of the "ten-over on the freeway" set, try driving the speed limit for a few days. You'll save a lot of fuel and your journey won't take much longer.
Under-inflated tires are one of the most commonly ignored causes of crummy MPG. Buy a reliable tire gauge and check your tires at least once a month. Be sure to check them when they are cold, since driving the car warms up the tires along with the air inside them, which increases pressure and gives a falsely high reading. Use the inflation pressures shown in the owner's manual or on the data plate in the driver's door jamb.
A dirty air filter restricts the flow of air into the engine, which harms performance and economy. Air filters are easy to check and change; remove the filter and hold it up to the sun. If you can't see light coming through it, you need a new one perhaps.
Jack-rabbit starts are an obvious fuel-waster -- but that doesn't mean you should crawl away from every light. If you drive an automatic, accelerate moderately so the transmission can shift up into the higher gears. Stick-shifters should shift early to keep the revs down, but don't lug the engine -- downshift if you need to accelerate. Keep an eye well down the road for potential slowdowns. If you accelerate to speed then have to brake right away, that's wasted fuel.
Keep your car speed at a constant move without accelerating the speed with moving and jilting your tires. A constant speed does not only minimize your fuel spending but also aids economy as it takes more fuel to get a vehicle unmoving than it does to keep it moving should shift early to keep the revs down, but don't lug the engine; downshift if you need to accelerate. Keep an eye well down the road for potential slowdowns. If you accelerate to speed then have to brake right away, that's wasted fuel.
Apart from these tips one can also save fuel by switching off the air conditioner inside the car whenever possible and by keeping a constant check on their cars parts and materials as new parts increase fuel efficiency. Last but not the least dont forget to periodically clean your car off all dirt and dust