whybuybeta-great tip, i read it before, i tested many times, really useful

actually they need garages in the zone, garage has a distance, around 2 times of his size each direction, maybe put a tenement near and the urban road lenght size, dunno exactly, but when something is out of range, they will build a shack

best favoured housing is most close to any garage, if one is 1 pixel away, then they wont move in

married couples put shacks between their job positions

putting blocks near workplace its useless unless have no garage around it
put houses instead, if you know they will use it
they pay 1/3rd of their salary, so try to build houses, they are expensive but married couples will choose it, you gain back the price, more kids and bad pay makes usually protesr them, so make some good house before this happens