Se when you are planning your trip being FT on other airline than CX, try to avoid CX as they will not give you amy miles. I was really dissapointed as almost half of my RTW trip was on CX and FT on AA. WI would have gain over 10,000 miles more toward my next tier using some other options (AY, JL).
My first RTW was with Star Alliance and I received full miles on each carrier to my EB, so I was kind of assuming same happen to here.... so better to check before you book.
While this is heavily dependent on your program and routing, you can often book a codeshare to earn more/full miles. For example L on CX earns 0 miles in AAdvantage and QF earns 50%. On TPAC routes you could likely book the AA codeshare and earn 100%. In business or first this isn't usually necessary in any OW program AFAIK as D/A earn the same regardless which carrier the code is booked under.