well occupying bases can be good and bad its anywhere from 4-30 extra credits an hour and good at pissing ppl off. if you occupy an inactive or npc keep it till a better one comes along. if its someone who can fight back drop the base unless you are having a war than at least keep a fighter on it it will cut their production eco and slow them down.
for building a base start out with metal ref. to get production and construction going then build robotics ( i build which evers cheaper) now if you have a metal 3 planet build the crap out of those ref. cuz you can make that base into a fleet spamming basterd.
build crystal mines if you got em (crystal 2-3 (you're not gana fine one with 3 there all taken) don't build bases on crystal 1 cuz its a waste every building except crystal mine gives you +1 to eco)
i build at first a lv 10 space port gives you 3 routes with 20 extra income.
for more info check out wiki you can learn so much on each page you read.
