Economy

Economy is the art of managing all the aspects of imperial production to maximize efficiency and productivity, without cost overruns.

Priorities

 * The primary concern of managing an empire is ensuring a positive cash flow. Credits are used primarily for rush-buying, but they are also passively drawn from the treasury to pay for the upkeep of existing colony structures, diplomatic deals struck with the other party (if paying tribute), and any cost overruns for large fleets.
 * Secondary priority is maintaining your current population. Losing a population unit means more than just a planet shrinking, as you lose the income it produced and any production. When in doubt, always divert colonists to produce food.
 * Finally, there is research and production. The priorities depend on the general strategic goal of your empire, but when in doubt, research points are always a good bet.

Maximizing efficiency

 * One of the key things to remember is that surplus production, research, or food do not carry over between projects. For example, if a planet generates 30 production points per turn, but the current project only requires 10 to complete, 20 points are irrevocably lost. As such, efficiency includes micro-managing colonies and ensuring that the colonists are assigned to productive purposes. If a research project nears completion, the planet is about to gain a population unit, or the current building is going to be finished, limit waste by moving colonists to other projects for the turn, so that you have a net gain with minimal waste.
 * Next, keep the costs down. This rather broad category includes fairly simple recommendations, such as prioritizing colony structures (build those that provide the biggest benefit in the long term, such as those increasing growth rates (cloning centers, for example) or the number of credits produced per population unit. Note the upkeep costs too, and don't build structures that don't benefit the colony.
 * Similarly, economical ship designs in the ship blueprint editor are usually more advantageous, as stripping expensive modules allows you to field larger fleets faster.