Some of these concepts may overlap with existing methods of the current civilizations but this is why you are here to share your own ideas. Good luck!
Greeks: Gain favor by prayers.
Egyptians: Gain favor by building monuments.
Norse: Gain favor by fighting and destroying things.
Atlanteans: Gain favor by spreading their civilization.
Chinese: Gain favor by building gardens.
Aztecs: Gain favor by sacrificing your own people and prisoners. (Probably a no brainer here).
Celtics: Gain favor by constructing buildings closer to nature (forests). Celt players have the ability to plant trees as well for favor and a natural shield from the enemy.
Mesopotamians: Gain favor by exploring more areas of the map. Less fog of war = more favors gained. Mesopotamian players can pump out an observer called baru or countless of them (also very inexpensive) and strategically place them all over the map. “It was believed that the gods expressed their will through “words” (amatu) and “commandments” (qibitu) which were not necessarily spoken, but were thought to manifest in the unfolding routine of events and things. There were countless ways to divine the future, such as observing oil dropped into a cup of water (lecanomancy) observing the entrails of sacrificial animals (extispicy), observation of the behavior of birds (augury) and observing celestial and meteorological phenomena (astrology) as well as through interpretation of dreams. Often interpretation of these phenomena required the need for two classes of priests: askers (sa’ilu) and observer (baru) , and also sometimes a lower class of ecstatic seer (mahhu) that was also associated with witchcraft.”
Maori: Gain favor by creating rivers and/or large bodies of water and/or beaches. Maori players can create large bodies of water and having their settlements be surrounded by it for defense as well.
Hindus: Gain favor by gathering wildlife animals into your city and letting them roam around.
Japanese: Gain favor by building torii gates. Generate more favor by constructing these gates at the entrances of your base. Note: you can create these anywhere even in water.
Slavs: Gain favor during night time. What do vampirs (vampires), vukodlaks (lycans), baba yagas, domovoys, etc… all have in common? They usually appear in the evening. Slav players are able to pump out these units during day time but their stats are buffed once the night time cycle sets in. Day and night time cycle and different weathers are a must. Eye-candy galore.
Persians: Gain favor by keeping the “Atar” or the holy fire alive. Fire temples were constructed for this purpose. Wood is then traded for favors.