6. WHEN SHOPPING FOR AN AIRFARE ONLINE, MAKE SURE YOU TAKE INTO ACCOUNT ALL TAXES AND FEES
Nowadays, the cost of your plane ticket may depend on how much luggage you're checking, whether you want to pay extra for an aisle or window seat, and more. God bless the fare wonks at Kayak.com and FareCompare.com, who have compiled charts listing every possible fee you can incur, airline by airline. Don't forget that overseas low-cost carriers can hammer you with surprise surcharges: One reader e-mailed me to say that a $20 Ryanair ticket had ballooned into a $340 flight. "The farther you get from the United States," notes Brancatelli, "the more you don't recognize intuitively what a fee could entail.

7. MAKE SURE INVISIBLE AIRFARE SALES ARE VISIBLE TO YOU
Fare sales these days are largely unannounced. Instead of taking out big newspaper ads, carriers target specific subsets of travelers—frequent fliers, holders of certain credit cards, people who've registered on their Web sites to be notified about deals—and alert them by e-mail. The easiest way to learn about\ unadvertised Web-only sales is to sign up for low-fare alerts from Airfarewatchdog.com and FareCompare.com.

8. USE STATE-OF-THE-ART TECHNOLOGY TO FIGURE OUT WHEN TO BUY YOUR PLANE TICKET
It's the question of the ages: Buy now or wait? One tool that attempts an answer is Farecast.live.com. It predicts, based on past fare data, whether the lowest price for a flight will rise or fall within the next seven days. Another tool, also based on past data, is FareCompare.com's best-time-to-buy technology, due out later this month: Enter your destination and the week you want to travel, and it predicts the exact date the fare sale will begin. There's also Yapta.com, which alerts you when fares drop (and will help you get a credit or voucher for the price difference if you've already bought your ticket). It also tells you when a frequent-flier seat opens up.

9. USE THE RIGHT WEB SITES FOR YOUR FARE SEARCHES
Kayak weeds through a multitude of different search engines to find the cheapest, most convenient itineraries. Orbitz gives you a financial incentive if you're flying a popular route that has volatile pricing: If you purchase a ticket and, between the time you buy and the time you travel, another Orbitz customer books the same itinerary for less, you get a cash refund of the difference, up to $250 per traveler. If you're flying a route that Southwest covers, always check Southwest.com too, since its notoriously low fares aren't listed in the search engines.