Even if you can`t hold onto a planet, take
it from your enemy. Then "demolish" every 
building except one. Make SURE you demolish
the main colony Hub. You get 50% of the 
money, and your enemyloses a planet. The 
population will surely revolt because their 
needs aren`t met. If they come back and align
themselves with your race, tax them 
oppressively. They will become your cash cow
until they revolt from you.

by unknown