If you have played Cityville for not less than a week or two, you may already have seen or used the HQ that becomes available after reaching a certain level or after doing some quest or requirements for your city. If you have indeed used the HQ then you will know that when you place it on your city, it gives certain percentage bonus to the stores that are placed near the HQ.
By exploiting this in-game benefit that Zynga has provided on the game, one can earn a lot more money on the game. Please take note however that this is not a Cityville Cheats. It's just one way of playing smart. For cheats, hacks and other tips and tricks on this game, read the other posts on this site.