[Ming]

Sorry for the late reply. My internet connection was down due to the damage to the trans-Pacific cables caused by the earthquake nr. Taiwan (most of Asia's connection to the US was impared).

Some of the "details" have already been mentioned by others. eg. build temples on all sea provinces so that land provinces come under your dominion. I shall add a few more:

1. Call Wraith Lord, which in turn generates ghosts. They compliment the Sea Trolls very well.
2. If in war raid coastal provinces with temples to destroy them.
3. Take coastal provinces with longbowmen or xbowmen and fortify them against all but large invading armies. Use the likes of murdering winter against large invading armies. Use these as your base for land conquest.

There are others but ultimately it depends on what your opponent is doing.