Maintain your car. Check your tires to make sure they have plenty of tread. Slipping tires are dangerous and they waste gas. Ask your car dealer or mechanic if you can use a lighter weight oil during the winter to reduce friction and save gas. Consider using a low-friction or synthetic oil to save gas. If it's been awhile since you changed your air filter, check your owners manual to find the recommended changing interval. A new air filter can greatly improve your gas mileage. Consider an after-market low restriction air filter system. Not only can these improve your gas mileage, but they often come with permanent filter media that can be washed or cleaned and reused. The higher cost of the after-market filter can be offset by not having to buy new air filters.

Check your tire pressure. As the temperature drops, so does your tire pressure. Low tire pressure is one of the most common causes of poor gas mileage and it can also wear your tires quicker and make your car handle badly. Check your tires regularly with a tire pressure gauge and make sure they're at the manufacturer's recommended settings. To find the recommended settings look in your owners manual or open your driver's door and look for a sticker on the rear of the door near the latch mechanism. Some cars have different recommended pressures for the front and rear tires. Don't overinflate your tires because that can make them wear out quicker and make your car handle poorly.

Don't run your car's engine to warm it up. This is a common way people waste gas in the winter. See your owners manual for recommended warm-up time for your car. It's usually less than a minute and often less than 15 seconds. Running your car's engine longer wastes gas. If you live in a very cold climate, install an electric block heater to pre-heat your car's engine. Consider bundling up in warmer clothes if comfort is an issue. If you're out shopping, park in a sunny spot and let nature help keep your car warm for your return.

Clear all ice and snow off your car before you start driving. In addition to being a lot of extra weight to haul around, ice and snow can increase wind resistance which also hurts gas mileage. Also make sure you're not dragging around any more weight than absolutely necessary by removing unneeded items from your trunk.

Remove your roof rack. If you use a roof rack for skis, snowboards, or other items, remove the rack when you're not using it to reduce wind resistance. If you must leave the rack on, at least remove the equipment from the rack to minimize the mileage drop. Consider using an aerodynamic box-style container on your roof rack for your winter sports equipment. If you transport sports gear or other items in your trunk or inside your vehicle, remove them as soon as you're done using them to save weight.

Avoid the drive-through. It's convenient to use drive-through lanes for coffee, food, or banking, but all that sitting in line wastes gas. Park your car and brave the cold to walk inside the eatery or bank and you'll save gas.

Bonus: Holiday gift suggestions to help save gas.

• For those on a budget, an accurate dial-type tire pressure gauge should cost you less than $15. Even the entry-level digital gauges are less than $20. Of course if you want a professional-quality gauge with superior accuracy or a digital gauge that tells you your tire pressure audibly, you can spend considerably more.
• If you're shopping on a higher budget, consider a GPS navigator. These electronic marvels listen to radio signals from orbiting Global Positioning System satellites and calculate your location with amazing accuracy. They can display maps, give you step-by-step directions to your destination, and even tell you where to find the nearest restaurant, gas station, or hotel when you're on the road. You'll never have to worry about being lost and you'll save gas by having a computerized navigator to direct you to your destination. The cost? An entry-level GPS navigator is under $90 and they range from there to over $1000 for a top-of-the-line model.