Well, there are few very important things.
After you have claimed a town, look at town info to figure out the demands of your town. On every 1st of month the town will try to build the needed industry for current demands, so it is important to have free space around your town.
For fast growth you have to do:
- fulfill town demands, growth time (days) will be change every month
- build some roads around town which are needed for building new houses
- pay attention to local authority
- some hidden features are available, pay attention to newspaper or chat.