Cityville Population Drop can Boost Population using less space. How :-

1. To increase the chances of Population drops and seeing your population increased is to collect often from your residential buildings. As in the case of Cityville TV Terrace is an example of a Population Drop
2. By Building Vertically, not horizontally.
3. To Boost Population using existing Business HQ Franchises, the higher your franchise, the more population you can store. It’s like a Mixed Development. Does not neccessary means it’s only for office use. I placed to many short looking Business HQ Franchises in my inventory as it is of no use.
4. Example, Tower Eats can also be used to house Population as well as a Maximized Business HQ Franchises (If you notice the Golf Course at the top of the Roof Top) it indicates Business HQ Franchises are at it’s maximum, creating a payout of 28%, surround it with your existing businesses.
5. The Higher your population, the Higher your towers are shold be the way to go.
6. For example the TV Terrace allows population of up to 350, but looks relatively same in size (which shouldn’t be), it should be in Tower-like, like Penthouse Towers.