Been playing the game for a week now and in my latest game I have five planets colonized after a colony rush. These planets range from 5 to 8 class. What I am finding a bit overwhelming is what and when to build on the colonies. I take advantage of any bonus squares but after that I seem to build in response to needs. E.g. if my population is low I build the recruitment center if the planet has a lot of income I build an economic building.  Also some of my planets don’t have nay building at all cuz of lack of money and/or space. I am not sure whether I should build a factory and or research building on each planet. In short I seem to not have a good grasp of what buildings are "essential" to my fledgling empire and which are more "luxury" items". Hope that makes sense. My over all goal is to maintain peace and then when ready start waging war on troublesome empires!