I never trade.
The key element seems to be not to build on most or nearly all colonized planets until the populations grow enough to make them relatively financially independent. Depending on racial bonuses, that number seems to vary from maybe 700M to 1200M. I tend to use 1000M as my default to begin building.
If I snag a high Q planet early, or one with some great tiles or great bonuses, then I do develop it some early and accept the hit.
Generally, I designate one planet to build scouts and then constructors then colonizers, while using the home world to constantly send out colonizers. It helps to be one of the races that starts with ion engines.
