Rack up more airline miles

There are more ways to earn airline miles than just taking flights.

(MONEY Magazine) -- If you only get miles by taking flights and using a rewards card, you're missing out.

"More companies are investing in giving out miles nowadays and I expect that trend to continue," says Brian Kelly, who runs the blog ThePointsGuy.com.

Use these tips to maximize your take:

Pick your eateries wisely.

More quality restaurants are joining up with mileage programs, says Kelly -- and airlines are promoting these loyalty programs heavily.

Send The Help Desk questions about maximizing your airline miles.

For example, United Airlines will give you 1,000 miles for the first $50 you spend within 30 days of signing up with its Dining for Miles program, which lets you earn miles by dining at one of thousands of participating restaurants.

Keep up with technology.

You can earn 500 miles on Hawaiian Airlines by following it on Twitter. And expect airlines to offer miles as an incentive to adopt new, less costly ways to check in, says Tim Winship of FrequentFlier.com. (This summer Delta gave 1,000 miles to fliers who checked in via its new app.)

Promotions tend to expire within a few months, so keep checking for offers on blogs like Boarding-Area.com's View from the Wing and Freefrequentflyermiles.com.

Pick your hotel wisely too.

More hotels are letting customers earn miles in addition to points. Starwood hotels is offering 1,000 Southwest points for stays through Dec. 15. And you can still grab more miles by paying the hotel bill (and the rental car) with an airline rewards card.