Trade
From Fleet
Trading is a great way to make money.
Tips & Tricks
Overstocking counts towards the Upkeep Factor. So if you can't find the things a planet wants, (greatly) overstocking it with cheap easily attainable things like or can get that Upkeep Factor above 1.0.<br\> As long as a planet's Upkeep Factor is above 0.5 it will recieve an increase in population, though the maximum population gain is achieved at Upkeep Factor 1.0, you can raise it further than 1.0.
References
The Planet list may be useful for helping you find the closest planet of a certain class, or for seeing the planet-type balance of each cluster.