First, in race selection, max the economic bonus. Consider Federalist Party, but their are advantages/disadvantage to al lof them.
Second, rush buy very few things early. If my homeworld has a bonus tile, I do generally buy to use it from the start.
Third, grow your pop by keeping 100% approval just about as long as possible. Thus, a few points in race selection to morale can be good.
Fourth, research at least the first econ bonus early.
Fifth, delay building anything on colonized planets until their pop grows enough to show a positive cash flow. This reduces expeditures and also maintenance costs. Be prepared to make an exception or two in the case of high PQ colonies or ones with juicy bonus tiles. Another exception might be to build a spaceport for more colonizers or constructors. For example, cheap zero engine colony ships can be used to finish colonizing a system, or add module to an anomaly mining base.
Sixth, grab any green anomalies you can, and add modules for bonuses.
Seventh, get a few more survey ships going, researching the sensor tech and also maybe Impulse engine (for the +1), though put only ion engines on them.
Eighth, get Trade and build the Econ Capital on your most populous planet. I get Trade for two reasons, and neither is to use freighters. The first is the Econ Capital, and the other is to trade it to minors for something (maybe cash) so that they will quickly start trading with ME!
Later, research Banks for the econ bonus. Also, researching morale buildings allows higher taxes even if one never builds the buildings. I generally do build at least one on the same planet as the Econ Capital, due to its high pop.