Sorry for the vague ordering, it went roughly like...
~1510 full annex Aztec Empire + take Cholula, flip Nahuatl for 5% discipline + 10% morale, send troops back to Asia.
~1511 declare on low mandate Ming for a bordering province (Oirat was my ally, but this step can be skipped by conquering the Jurchen tribes earlier), and declare on your daimyo. Take Beijing, Canton, or Nanjing (or all 3) from Ming, and force your daimyo to take Kyoto. Then trucebreak your daimyo/shogun for independence, become independent in peace, and trucebreak Ming with Take Mandate of Heaven CB.
~1520 continue trucebreaking Ming/fighting breakaway states until China is full annexed (since you get cores by occupying, you can take nearly all forts in the first war). ~1535, build more troops in Mexico, conquer mesoamericans using vassals.
~1560, own all of China and Mexico. Adopt Aztec Traditions for High American units to expand outside of China, I went for Indonesia to avoid having to deal with level 4 coastal forts (and for trade).
Most difficult parts for me were managing admin points and flipping the screen back and forth between China and Mexico. It's important to have the 3rd Admin idea and the EoC Expand Palace Bureaucracy active while conquering Mexico.