Always add a frequent flyer number to your airline reservations even if you don't generally use that airline. And make sure to check the airline because you'll sometimes receive extra baggage allowance if you're a member (such as the case with Bangkok Airways). While some airlines are a part of an alliance (OneWorld, SkyTeam & StarAlliance), others such as Emirates and Alaska have shared loyalty outside of an alliance, so plan out your year's trips to maximize status. Otherwise, you can use those miles to get free magazines, lounge access, upgrades at hotels or always gift them to a charity of your choice.