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Remember that time your friend said he flew across the country for free thanks to his credit card, and you were confused? You should keep reading. Banks compete for business by offering perks when you sign up for their cards and then swipe them — a dynamic that's been heating up lately. "It's a very, very good time to shop for credit card rewards," said Matt Schulz, chief industry analyst at Comparecards.com. Navigating the world of points and cash-back deals can seem daunting, but the average American could earn close to $400 a year if they just put their usual expenses on the right credit cards, according to Creditcards.com. One important note: People who carry a balance on their cards should stay on the sidelines of the rewards game, said Ted Rossman, an industry analyst at Creditcards.com. "The math just doesn't work: 2 percent cash back on a 17 percent interest rate is a losing proposition," he said. Here are simple ways to get the most out of your credit cards.

Know what you're looking for, and where to find it

The best advice for picking a card is to "know thyself," Schulz said. "Ask yourself how you plan to use the card and what you want to get from it," he said. "Once you've honestly answered those two questions, you'll be on the right path." You can compare different cards, and what they offer, at Bankrate.com, Creditcards.com or Comparecards.com. Don't forget to open your mailbox, too, Schulz said. "Credit card issuers are still sending targeted offers to desired customers," he said. "Those offers can sometimes be different from any you might see online."

Make the most of your current spending habits

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"The best way to maximize credit card rewards is simply to get a credit card that best fits your lifestyle," Schulz said. The average American spends $6,477 on groceries each year, according to Creditcards.com. If they used a card such as American Express's Blue Cash Everyday Card, which offers 3 percent cash back at supermarkets, they'd pick up $185. "There are cards that give you bonuses for old standbys like gas and groceries," Schulz added. Dine out a lot? The Uber Visa Card offers 4 percent cash back at restaurants. Bank of America's Cash Rewards Card will earn you 3 percent cash back on gas, which the average person spends $1,899 a year on, Creditcards.com found. For frequent travelers, Rossman recommends the Wells Fargo Propel Card from American Express. It gives 3 percent cash back on travel, and there's a $300 sign-up bonus if you spend $3,000 in the first three months. Avoid redeeming points for items that will leave you with other expenses you can't afford, said Bruce McClary, vice president of communications at the National Foundation for Credit Counseling. For example, a free airline ticket will mean you need to shell out for accommodations and dining. If those purchases will sap your budget, he said, consider using your rewards for more practical items such as gas or food.

Swipe, then get reimbursed

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Try to rack up rewards for expenses covered by other people. In their pursuit for rewards, for example, some people will put the entire check on their credit card when they're out with their friends, and then get reimbursed. But if you have to chase down people to pay you back, this strategy could backfire. You might charge work expenses on a personal card, Rossman said, so long as the move flies with your boss. Before you do, consider how quickly your company pays you back. "If they take a few months and you have to front a large bill in the meantime, it may not be worth tying up your own funds for that long," he said. "As long as you can pay your bills in full, put everything you can on a credit card to earn the rewards," Rossman said.

If you want to get a little more serious

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