I'm not sure what is so difficult about this. Pick a few airlines (those that you fly most) and join their FFP. Avoid duplicating within an alliance (so one Star Alliance, one OneWorld, one SkyTeam). If you are US-based you might want to join those of United, American, and Delta. Go to their respective websites. There are a few major airlines which are not in a FFP (Virgin Atlantic, Emirates, etc) so join those programmes if you fly these airlines. When you fly on a Star Alliance airline, enter your UA details, a OneWorld airline, enter your AA details. Gain points. After plenty of flying you might be able to redeem for a semi-free flight.