Need goods for real needs. One type of good for one fief. Ex: steel for make looming weapons. leather, steel and something else for looming armor. Food for population. population for troops. You never make toops more then population. +1 troop = -1 man from population. etc. Nofraction players may work for owners in the town servitude for making goods, then sell it in the town marketplace. Transfer strat gold into cRPG gold, was a good stimulus for nofraction players to earn extra income while playing strategus. But it dont be easy. 1 to 2 no more. After this. Owners can make real S&D for trade.
But all of this not possible yet