Master of Orion: Conquer the Stars/Colony Management

Do not overbuild
One of the quickest way to hamstring your empire's growth is to over-build structures on the colonies. Example, building pollution control structures on a volcanic planet (and you are not playing the pre-configured Silicoid race). You can do so, but all you will do is eat up credits. Advise: build only what is needed and ignore the rest

Hire only the needed leaders
During the game, various leaders will present themselves to be hired. Hiring too many managers will bite you later on when they get their pay raises.

Support Structures
Try to alternate between building support structures and building ships. Colony ships and Civilian Transport ships will snatch away one of the population of the planet. Build Food technologies (like Hydroponic Farm, Fungal Farm and Soil Enrichment Facility) to get the population growth as high as possible. Keep an extra population in the Food area of the colony. It is important to get the Star Base built as quickly as possible per each planet. A Star Base will provide 5 command points which will in turn help you build up your fleet.

Ship Building
During the beginning of the game (expansion time), alternate between building war ships and colony ships. Do keep an eye out on the command points of your empire. As each Military Outpost, Frigate ship or Colony ship are built, they will use 1 command point. Larger ships will take more command points per ship built (example: the Destroyer ship takes 2 command points per ship)

Research
Researching new technologies is very important in order to keep up with or surpass the competing races. Build research facilities as quickly as you can. Use the research map to select a path of technologies to research in succession.