Scott Lynch, Jayme Lynn Blaschke, Rob Rogers, and Vincent Docherty in the City Building panel.
Scott Lynch also suggests that if you want to get a handle on realistic city-building, try to develop an interest in solid waste management. Combing through other people's waste used to be a major part of people's pastime in medieval and even early industrial times. Masses of poor people would wade in the sewers, capturing lumps of waste, and picking out anything that was remotely valuable, discarded by upper classes. In Victorian England cities, that had long outgrown their medieval infrastructure, there were thousands of people involved in the business of transporting other people's "nightsoil". All this was a subject of Steven Johnson's book "The Ghost Map: The Story of London's Most Terrifying Epidemic--and How It Changed Science, Cities, and the Modern World", that Scott Lynch got his wife for Christmas. That's the kind of guy he is! :-) (In his defense, he said his wife is a biology major, and fascinated by pathogens.) Even if you are not into pathogens, stuff like this surely helps a fantasy writer to create a realistic medieval world.
Pictures from ArmadilloCon 2009 are in my photo gallery.