Discounted Tickets and Frequent Fliers
It makes sense to subscribe to a frequent flier program, as now there are many ways to build points. Besides earning points from you trips, there are now credit cards available that can add points to your totals with every purchase. If this is a priority for you, you can run all of your purchases through the card.
Now with airline alliances, it is possible to build your frequent flier miles with one airline, and redeem them with another. The program that you 
sign up for should be the one that covers the routes you travel most frequently. But you may also want to consider who the partners are with the program, as this may play an important role at redemption time.
Some strategies to build up your miles may include a couple of short cheap flights when you are close to a redemption level. Some airlines give you a minimum number of miles for each flight. Also you may find you are granted better mileage credits if you plan a trip through an intermediate city rather than a direct flight. Follow the promotions offered by the airline carefully. Check your statements and the airline’s web site carefully so that you can take advantage of the promotions.
Be sure that you understand how to properly register and receive credit for the miles earned. It is a good idea to keep your boarding pass until you review your statement to ensure that the miles were properly recorded.