I'm pretty new at the game and I don't understand the concept of military production, social production and research.
If I build a factory I get some kind of production capacity. If I don't use it, then it's wasted. Wasted military production doesn't waste BC, but social production does. But if I change the production assignement, then I can 'save' BC by moving social production to military production. With a production focus I can reduce the problem a bit more, but it then also reduces research. I guess the best thing would then be to have one production planet with a focus on military production, constantly building ships and let all other colonies on minimum production because their production is wasted anyway and buy all planetary improvements.
I'd also like to know how to find out the max population of a planet and how to increase the population growth rate.
Approval seems to be some kind of moral, just more complicated. I don't understand how the population size can affect this value. I'd have guessed it's just a percentage value of the happy/unhappy part of the pop.
I had a look at the Wiki, but it wasn't really helpfull.