Look into partner airlines and alliances. “If you have enough American Airlines miles, you can fly across the Atlantic on British Airways or Iberia,” says Mark Ashley, a travel expert and the founder of www.upgradetravelbetter.com. (Search for alliances at www.airlinetechnology.net.)

Consider branching out. Flying into a lesser-known airport may allow you to use miles you otherwise could not, says Kurt Stache, a vice president of American Airlines and the general sales manager and former head of its AAdvantage program.

Check early. Frequent-flier tickets can go on sale 11 months in advance, so for the best chance of getting a seat, book ahead. Ashley recommends picking up the phone when you’re trying to book. “Even if the airline charges you a fee, it’s worth it to talk to an agent. An online search of one airline won’t pull up award flights on a partner airline,” says Ashley. “You have to pick up the phone for that.”

Consolidate. You’ll earn award travel faster if you do most of your flying with one airline or within one alliance group. And don’t open accounts with multiple airlines in the same alliance. “Northwest, Delta, and Continental are all in SkyTeam, for example, so if you have mileage with Northwest and fly Delta, don’t open a Delta account. Credit the miles to your Northwest account,” says Ashley. Those who already have small balances in multiple loyalty programs can exchange miles through a conversion website, such as www.points.com.

Look alive. Most programs require members to earn or redeem miles regularly — at least every 18 months, say — in order to retain those that they’ve accrued, so keep your account somewhat active.

Get a quick fix. If you are within a few thousand miles of a reward and are planning a vacation, you can top off your miles almost instantly by purchasing more. But, Ashley warns, this can sometimes be a rip-off. A better option may be to sign up for the airline’s credit card. “Some offer bonuses of up to 25,000 miles for the first purchase,” he says.

Explore your options. If you still can’t book a flight with your miles, don’t sit back and let them expire. Upgrading, sometimes for as little as 5,000 miles, is one of the easiest ways to use miles, Stache says. They can also get you free car rentals and hotel stays. Better yet, donate miles you’ll never use to worthy causes, like Make-A-Wish, UNICEF, and Operation Hero Miles.