Resources are the backbone of your empire. Falling into a deficit can end your campaign.
Check the State Decisions menu regularly. These are unique political or social actions that can grant powerful buffs, though not all factions have access to the same ones. Imperiums.Greek.Wars..v02.12.2022.part2.rar
Build roads to connect your cities and blacksmiths to mines within 3 tiles to maximize output. Resources are the backbone of your empire