Hi!
I am looking for a solution for my issue - when a territory for example city is full but need to keep developing. No more buildings inside, no more updates. It should start conquer the territory around, primary desert and the player should spent money and assimilating something. But what?

In other words imagine that you are playing a strategy where there is no enemy but you should conquest the world. What could be your obstacles? After each success city's territory's influence will become larger. For example it could assimilate villages around, convert desert to usable soil, wild flora to cultivated, find out ores...

The problem is that in some point for a limited time the player can not take new territories and it will become boring if he cant use some of the cities for anything except production.

invest in the arts to raise moral? invest in education to increase research? encourage propaganda to make invasion easier? 

23 hours ago, Pleistorm said:

What could be your obstacles?

Anything ?? the world is big, so.

most games use military but if you have another theme go with your theme.

23 hours ago, Pleistorm said:

The problem is that in some point for a limited time the player can not take new territories and it will become boring if he cant use some of the cities for anything except production.

Assuming your game is RT: increased speed-button.

5 hours ago, Dramolion said:

Assuming your game is RT: increased speed-button.

lol yep that'll do it  You might also do what Tropico does best: allow your players to micromanage workers, leaders, etc. Also, include random events such as catastrophes and discoveries to keep it exciting and unexpected.