You could add more farmhouses to the regions surrounding the cities that could realistically have 10+ NPCs each by placing the Lord of the Manor, his children, wife, and servants inside the manor. Outside there could be some farmland and a few peasant shacks. The peasants work the land and never enter the Manor. Add some poor kids running around and you have yourself a realistic population in a relatively small area. For specific recommendations, I think you could make all the buildings in Riften one story higher and add Tenements/Apartments you could fill with poorer residents. The Ratway could also be expanded with "safer" zones filled with the poor Whiterun: more farms, like i described above Windhelm: more farms and mills along the river... it's a huge river, there should be lots of mills using that potential Winterhold: maybe rebuild some of it, I know it got destroyed but it doesn't have to be a village now Dawnstar: add more docks and buildings Solitude: build slums outside the walls and under the sea-arch and further along the river.. this city should be much larger than it is Falkreath: add more hunter camps and maybe a new village somewhere, and expand the graveyard.. NPCs say its huge but the one in Windhelm is even bigger Markarth: just make it way taller, you could also make the Warrens much deeper