Summary of my and other posts .... for those battling with the economic aspects of the game.
1. All buildings require pops to operate them. Building anything when you dont have pops will cost you maintenance for an unused building, and worse, the AI will distribute your pops differently across the available jobs than you might have intended. Rule: only add buildings when you have pop to work them. The sector AI is good at reducing the micro here but again may not build the same things you might have.
2. Planet tiles produce raw resources (energy, minerals, food). These are the foundation of your economy and all else is derived from it. Rule: you need a healthy surplus of each, especially minerals.
3. Building tiles are unlocked by pops. 1 building tile for every 5 pops. After 80 pops no more buildings. Buildings produce 2nd tier resources (unity, research, alloys, consumer goods, amenities). Rule: aim to get 80 pops minimum on each planet to fully exploit it.
4. Pop growth speed is linked to your capital building, which can be upgraded as your population grows. The upgrades unlock at 10, 40 and 80 pops. Rule: You want to get to 10 pops rapidly. Resettlement helps but can be painful.
5. The market is a good safety net, and an emergency resource converter, but is less efficient than having a healthy econ in the first place.
6. Specialising a planet will unlock a 5% bonus for that resource, and makes the planet unique buildings super worth it (stock exchange, resource institute, food processor, mineral purifier, energy nexus). Because all resources go into a global resource pool there is no penalty for a planet running a deficit on any resource.
7. Upgraded buildings produce 2nd tier resources at exactly the same rate per job as the base building. They just offer more jobs and costs a strategic resource as well. The advantage to upgraded buildings is that the energy maintenance is less per job, and you are squeezing more jobs out of valuable building tiles. Upgrades also dont contribute to empire size. Rule: dont rush to upgrade buildings unless you have a surplus of strategic resources and pops, a shortage of building tiles, or you are fighting the admin cap.
8. Administrative efficiency will serve as a brake for rapid growth but generally the benefits of going wide outweigh the penalties. Improving your admin cap reduces the penalties but trying to operate at zero penalty (tall) is not worth it economically. It is of course fun for roleplay or if you want a challenge.
Tip: If you find the whole thing intimidating or micro intensive.... set the sector AI priority to production, give it some minerals to play with, and leave it to build your planets. Just check your queues from time to time. It's 5% to 20% less optimal but 80% less micro.