The Mileage Game: How to pick a mileage program, step by step

Picking the right frequent flyer program is the first step towards bending the mileage game in your favor, and the choice goes beyond simply which airline you fly the most. Here is a step by step guide to picking your mileage program(s):

1. Find out which airlines are based in your city: If you live in a hub city for a certain carrier, that often determines what airline alliance you’ll end up in because there are more inexpensive flights on the carrier based there. If you’re not a hub city, find out which airlines are fighting for your city and consider joining one of those.
2. Research the alliances: Airlines form cooperative alliances which mileage can be earned and redeemed on partner airlines. This means that even if you’re flying Lufthansa, you can still earn mileage in your United or Continental mileage account. The three major alliances are Star Alliance, SkyTeam, and oneworld. For those of you in an Alaska Air hub city, Alaska has their own unique constellation of airlines which includes carriers from both SkyTeam and oneWorld, but with the draw back that if you achieve elite status there are fewer perks and there are some limitations on how you can redeem your miles. On the other hand, these one off airlines can open up unique opportunities. For example, Alaska Air partners with Kenmore Air, which operates float planes from Lake Union in Seattle. For 10,000 miles you can get a round trip to any of their uniquely northwest and often remote destinations, plus amazing views of the northwest thanks to their low altitude flights.
3. Take a look at your history and figure out who you usually fly with. Although this doesn’t bind you that airline, but again it gives you yet more insight on what alliance you should invest in.
4. Once you have an idea about what alliance would suit you best, it’s time to start reading through the frequent flyer sections of each airline. You want to pay special attention to what fare classes earn miles on what airlines (for example, for my United account if I fly SAS on some common discount economy tickets I earn 25% of the flown miles! Because of this, I usually fly Continental or, better yet, Lufthansa, where I earn 100% of my flown miles (and an elite bonus on top of that), even if there is an extra stop involved).
5. While you’re there, you’ll also want to double check the redemption section and learn about how many miles you need to get your free ticket. Some programs are simply better than others, but the average right now is about 25,000 miles for a domestic ticket and 50,000 - 55,000miles to Europe.
6. Don’t forget the bonus miles! If you are willing to sign up for a credit card, or jump through other hoops, you can land a healthy chunk of miles pretty quick. There are fees attached to these credit cards, so they're not free, but if you plan on closing the card or converting it down to a lower fee or no fee (if available) card, you can come out ahead. Other times, there are free miles for things like signing in online, or flying certain routes with that carrier. 
7. Lastly, (and perhaps most importantly) some carriers have better odds of redeeming miles than others, so be sure to do your research! If you have a million miles it doesn’t matter one bit if you can’t find a seat to spend them on! A fairly recent survey (at time of publishing) can be found here.

At this point, it’s time to decide: You will have to weight these factors yourself, but the best program will give you the most options to the most places with the most opportunities to earn 100% mileage and the greatest chance of redeeming for a seat. It’s also a good idea to sign up for a secondary account with another airline that covers the other alliance(s), so that you always have some place to put your miles just in case the fares are so much less that it doesn’t make sense to fly within your primary carrier.