I find a good strategy is to up the population as much as possible, as they generate enough wealth to support all buildings and then some. If there is room for it, I add economy buildings. I also add space stations near every colony and add economy modules to those. After a while, the economy shoots through the roof!
A good tip for local space stations is to design a stripped down version of the constructor ship, as they get very expensive after a while as they automatically upgrade... But, with a stripped down version you can build one in 1 turn at even the least productive shipyard.
