CREDIT MILES TO PARTNER/ALLIANCE AIRLINES

As always most often than not folks buying the revenue ticket are concerned about getting the lowest priced ticket that works for them without any consideration to airline miles earned. For e.g. you might find a flight which has a lowest fares that works for you but does not earn any miles as the ticket might be "highly discounted". But unless you are flying airlines which does not have "any" partners or does not belong to any "alliance" there might be some opportunity to earn miles even though the airlines you booked your flights on does not provide any such mileage credit. Make note of below pointers which would help you earn those miles!

• Make sure you know the "class" in which your ticket is booked. This will be through the carrier you booked the ticket from. The info will help you determine if you can earn miles and how much. For each ticketed itinerary you will always see the "class" mentioned in the details of the ticket.
• Find out who are the other "alliance" airlines or "partner" airlines to which you can credit those miles to? For e.g. if you are flying American Airlines (AA) you can credit your miles to any of the "One World Alliance" airlines or any of the "partner airlines". For e.g. you could credit your miles to Cathay Pacific (CX) or Alaska Airlines (AS). 
• Find the mapping of "class of service" between the carrier you booked your ticket through and what "class" it maps to for earning miles on alliance/partner airlines.  (If you booked your itinerary through 3rd party travel site, check out the airlines webpage on which you plan to fly for details.)

Case 1: You booked the Cathay Pacific (CX) flight in "S" class which would not be earning any CX miles:
Knowing that "S" class would not earn any miles on "CX", you would want to find out if any of the "alliance/partners" provide any mileage credit for "S" class of service. Doing a little research you will see that "British Airways (BA)" provides 25% credit of miles traveled in "S" class while "Finnair (AY)" provides 50% of miles traveled as of this writing. You would need to check out the "relative value" of 50% earned miles to 25% earned miles and decide accordingly. But just using the Frequent Flyer membership number of either of these programs would be a great idea for crediting your miles to them rather than not receiving any miles. You can check out the "chart" for BA here and for AY here. 

Case 2: You booked the Qatar Airways (QR) flight in "V/W" class which would earn 25% of actual miles:
Doing a little research you see that Qatar Airways (QR) is a "partner" of US Airways (US) (One World Alliance member) and Asiana Airlines (OZ) (Star Alliance member) which earn 50% of actual miles flown as well as give you access to use those miles for redemption on either One World or Star Alliance. Thus becoming Frequent Flyer (FF) member of either of these two and crediting your miles to them you would not only get a better earning rate but also access to other "alliance" airlines awards. You can check out earning for QR here, US here and OZ here.

Thus checking your options for mileage credit can open up more opportunities than you can think of :)