Planetary industry is a method of passively gaining resources that can either be sold on markets, converted to higher tier PI resources, or used to make other items in industry or reactions. As an example of how to set up PI, the video below shows how to get set up to produce Robotics:
https://www.youtube.com/watch?v=4va80y0C3j4
Interested in doing PI to support operations in the Convocation of Empyreans or support the Gallente Militia’s war efforts? We recommend setting up your PI in the low security systems of Heydieles and/or Fliet. Diplomatic arrangements have been made to lower the POCO taxes in those systems to 5%, and Heydieles is a hub of operations for industry, marketing, reactions, and a collection point for CoE’s Buyback Program.
CC upgrades:
Improves your planet’s CPU and Powergrid. This allows you to have more factories and to stretch your extraction heads farther away from your P1 factories (or to have more extraction heads).
Interplanetary Consolidation:
One extra planet per level.
Planetology and Advanced planetology:
These make the heat map showing where there is more resources to extract on planet surface more precise. Not really necessary but nice to have.
Remote sensing :
Shows you the amount of resources being extracted while repositioning your extractors heads as well as the heat map for resources. Train it to 3, maybe 4, no need for 5. (You can access your PI planets from anywhere in New Eden without this skill.)
Train these first for your 3 characters (1 account): Command Center Upgrades to lvl 4 Interplanetary Consolidation to lvl 4 Planetology to lvl4 Advanced planetology to lvl 3 Remote sensing to lvl 3 (this is not an essential skill but the training time is short)
If needed, after training your 3 characters for the skills above, you can train Interplanetary consolidation to lvl5 to get 1 more planet per character. CC Upgrade to lvl 5 isn't really necessary¹.
(¹) It was already highly debatable if the extra CPU for your planets was worth the long training time of CC Upgrades lvl5 unless for really advanced and complexes extraction + factory setups in the same planet. Now with the new upgrade to the PI size (it has been halved), you don't need to upgrade your links for your extractors anymore so it’s even more debatable now.