Wealth - focus on making money (gives more $ to you but weakens your military strength)
Science - focus on research (gives medium $)
Military - focus on ships, resistance, starbases and buildings to help military strength (gives less $ but helps in resistance and other ways.
Diplomacy - balanced
Research an item in Age of War to increase loyalty of a Common Wealth.
Trade with them the cost is less then the market.
When a Common Wealth is formed have the option to set it up to the way you want it or use defaults.