How to beat rising gas prices (MoneyWatch) How angry are you about rising gasoline prices? Well, you'll probably get even more upset as prices escalate into Spring. But don't let that anger translate into an aggressive style behind the wheel, which will only cost you gas mileage and money. Gas prices, at a national average of $3.81 already up 31 cents a gallon from a month ago, will rise again as refiners shift over to more expensive summer blends containing smog-fighting additives. That's the forecast of analyst Tom Kloza of the Oil Price Information Service. Kloza sees the national average gas price reaching $4.25 by the end of April, eclipsing the previous high mark of $4.11 in 2008. And that high price could soar much higher if an incident with Iran crimps world oil supply. You can't control any of that. So why not focus on what you can control: Your driving style. Yeah, you have probably heard at least some of this eat-your-spinach advice before. But the cost of filling your gas tank now makes it worth paying attention this time. Here are some gas saving tips, partly based on research by analysts at the automotive site Edmunds.com: Don't tailgate. You already know that shadowing the bumper of the car in front of you is dangerous. But constant braking and then accelerating again hurts gas mileage. Don't change lanes aggressively. If you are caught in a traffic jam, the speed of different lanes in getting past the obstacle ahead will eventually even out. Use cruise control. Out on the interstate, drive at a steady speed instead of faster, slower then faster again. Setting cruise control to match the highway traffic flow instead of constantly speeding up as much as possible gained 15% in fuel economy, the Edmunds test drivers found. Keep luggage off the top of the car. Road trip. Your first instinct is to load the family's gear atop the roof rack. Don't do it if you can possibly stuff it inside the vehicle. Rooftop luggage and its increased air resistance cut mileage by 21% in this test. Avoid idling. If you must sit outside a store or mall, turn the engine off. Otherwise, you are in effect getting zero miles per gallon. Check your tires. Under-inflated tires are unsafe, and they dent fuel economy. Tires inflated one-fourth below the recommended level result in using 3% to 5% more gas. Finally, buy the least-expensive gas you can find as long as you don't have to travel too far and offset your savings. Check a site like GasBuddy.com that will give you the lowest prices in your area. A check of the New York City area where I live showed $3.83 for the best price and $4.49 for the worst -- a difference of 66 cents a gallon.