How can I increase my delegate count?
The base number of delegates each Civ gets is based on the era. The host of the congress starts with an extra delegate, which increases as the base number of delegates goes up during the Eras. The host is voted on again each time the congress enters a new Era. Once the Industrial Era has been reached, city-state allies provide additional delegates.
According to in-game Era-change pop-ups:
- Renaissance Era: 1 for being a member, +1 for being the host, and +0 per allied city-state.
- Industrial Era: 2 for being a member, +1 for being the host, and +1 per allied city-state.
- Atomic Era: 3 for being a member, +2 for being the host, and +1 per allied city-state.
- Information Era: 4 for being a member, +2 for being the host, and +2 per allied city-state.
The Forbidden Palace Wonder gives +2 delegates.
The Globalization technology gives +1 delegate per spy assigned as Diplomat you have in another Civs Capital City.
If the World Congress enacts a World Religion, you get +2 delegates from being a member of that religion.
If the World Congress enacts a World Ideology, you get +2 delegates from being a member of that ideology.
You can also trade votes with other Civs through the Diplomacy screen provided that you have a spy assigned as a Diplomat in their capital.
There are a few ways that you can gain delegates throughout the game.
The player hosting the congress gets one* extra delegate, but only while they are the host. The player that builds the World Congress is the first host. From then on the host is voted in using the same process as enacting legislation.
* IIRC this bonus increases through the eras.
Each civilization gains one delegate once everyone has progressed to the next era.
Beginning in the Industrial Era, you gain one delegate for each city-state ally.
You can trade delegate votes for the next session using the normal trade mechanics.