Supporting

Support is crucial in every alliance and this is one of the factor that will say if an alliance swim or sink. Pay attention, because revolt and conquest worlds have different ways in defending.

Revolt Worlds

A city is in revolt, how many troops should I send?
If the request is DLU, try to send 6x swordsmen, 2x archers, 5x hoplites. You will send around 25%~50% of your troops. But if you are in a safe area, then send all your troops in fast transport boats. A wall level 15 or higher is required.
If the request is birremes, it’s the same thing, send 25%~50% of your ships. But if you are in a safe area, then send all your ships. If a city has many biremes, then a colony ship will never be anchored.
Avoid send birremes and DLU together, focusing in one type of defense is better than spliting your defenses.

Conquest Worlds

A city is in siege, what should I do?

To help the poor guy, you must break the siege, sending an powerful attack.

If you are in the same island, then send a land attack, if you are in another island, then break the siege with light ships.

There are a CS incoming, what should I do?

Send birremes to sink the CS.

Any doubts post in the comments.
Thanks.