I am new to the game: but not the style of the game.
I believe there should be additional buildings for your provinces.
You get the point.
These need to be added into the game so you can get additional resources out of your lands.
If one of your provinces has a wood icon on it; then build a lumberYard to get a bonus out of it. Or if you do not need the wood bonus but need more food; build a farm on it.
Fish Farms can only be added via coastal water of course.
But this will bring in more rewards for big wars that are fought. Just my opinion.