Tim Leffel, author of “Make Your Travel Dollars Worth a Fortune,” flew roundtrip to Eastern Europe, Southeast Asia, and South America last year using miles acquired through his credit cards. His flights would have cost $5,500. Instead, with creative spending, sign-up bonuses for his two American Airlines credit cards, and some online research, it cost Leffel 65,000 miles and $170 in taxes.

Brian Kelly, a former Morgan Stanley associate who runs ThePointsGuy.com, racked up 500,000 points from credit card rewards in one year. Using these points, he took a 10-day trip to Paris and the Seychelles worth $15,000. He also flew round trip to South Africa — in first-class seats valued at $7,500 — for $125 in taxes and 110,000 miles.

“The juice and glory in frequent flier miles is leveraging them,” says Kelly. “You can travel a lot better than you ever thought you could if you just pay attention to how to get miles and redeem them.”

Credit cards are one of the easiest ways to earn miles, points, and cash back. With so many variables, however, it’s important to find the card that best suits you and your travel needs.

The following tips can help you determine the right card:

AIRLINE-SPECIFIC CARDS

If you tend to fly a particular airline, consider getting that airline’s credit card, such as the Gold Delta SkyMiles card or the United MileagePlus Explorer card. You typically get a hefty sign-up bonus, often enough to take a free flight instantly, and travel perks such as a free checked bag, priority boarding, and extra mileage credit if you use that card to purchase flights. Certain Alaska Airlines and US Airways credit cards even offer $99 companion tickets each year. Sticking with one airline gives you additional perks. Earn enough points on an airline credit card, for instance, and you may receive priority check-in, free in-flight Wi-Fi and media players, and airport lounge passes.

GENERAL TRAVEL CARDS

Some travel credit cards, like the Chase Sapphire Preferred card, offer bonus points upon sign-up (after making qualified purchases) and let you earn points with every purchase to pay for flights on many airlines and for other travel services, from rental cars to Broadway tickets. Or you can sign up for a cash-back travel card, like the Capital One VentureOne card.

HOTEL-SPECIFIC CARDS

These work like the airline cards and typically offer sign-up bonuses. The Marriott Rewards Premier credit card, for instance, offers 50,000 bonus points if you charge $1,000 within the first three months, and gives you one free night when you sign up and a complimentary stay every year on your sign-up anniversary. With a hotel credit card, you earn points for purchases, often one point per $1 for any purchase and up to five points per $1 for purchases at the property. You may receive other bonuses once you start racking up points, like easy check-in and check-out, room upgrades, complimentary parking, and free breakfast.

CONSIDER THE APR

Make sure you check the annual percentage rate (APR) before signing up for a travel rewards credit card. Their APRs tend to run higher than other credit cards, typically between 15 and 25 percent, so if you will have a balance from month to month, you may end up paying more in interest fees than you’ll gain in travel rewards.

PAY ATTENTION TO ANNUAL FEES

Many travel rewards credit cards have annual fees that cost up to $95, but can run as high as $495. Make sure the benefits you receive offset the fee. Typically, if you get a free night’s stay at a respectable hotel, or if you take at least two trips a year and get free checked luggage each way, you’ll cover this fee in no time.

ASK ABOUT FOREIGN TRANSACTION FEES

Before traveling outside the United States, find out if your credit card company charges a foreign transaction fee, which can boost your bill by up to 3 percent of what you spend while out of the country. Capital One and Discover typically waive these fees. Some companies, like American Express, have dropped the fee on their premium cards.

IMPACT ON YOUR CREDIT SCORE