Frequent flier miles

As soon as you get to know that your travel plans are finalized, decide on which airline and consequently what alliance of airlines you would want to join to start earning frequent flier points. Pick one airline and try to remain as loyal as possible to it. The miles you earn will provide some succour to the dreariness of travel.
There are 2 major airline alliances out there, Star Alliance and One World. You can google to check which airlines belong to which alliance. If you are an individual traveller (as opposed to a corporate traveller) cost of airline ticket plays a really big role. At that point it doesnt really make sense to worry about alliances and frequent flier points because you would be loyal to what ever airline that gives the best price. Even there, it makes sense to check British Airways or Cathay pacific to see if it has any good deals. They are part of One World alliance and you may stick to them in future as well since they have some really competitive pricing.
The world is your oyster if you are a corporate traveler (without any budget) Depending on which region you travel to most frequently (US, Europe of Asia) you can pick your airline - Lufthansa's Miles and More is very popular because they cover loads of US and European destinations and you also earn miles on almost all classes of economy (Unlike some other airlines)
Contrary to popular belief, all economy seats are not priced the same. There are some which are at a higher rate than others on which you will earn complete miles. For some really cheap economy seats you may not get miles at all. For some reason, Luthansa doesnt seem to offer really cheap seats to corporates and hence you will end up earning miles on all your flights (albeit your company might be shelling out more for indulgences)
Companies usually have some price band from the cheapest airline within which you will have to pick your choice of flights. To get your pick of airline, try to communicate your travel requirements to your travel desk as early as possible.
Of course, when its time to redeem your miles for a free international ticket remember these points:
- You will still have to pay the taxes
- Book your tickets well in advance as there are not too many seats available for this quota.
- If it as international alliance (like star/one world) redeem for international flights. You will have to shell out too many miles for one domestic ticket.