@farscape72643 From the 3rd post in the thread, there are examples of ways to increase your bonus:
http://i.imgur.com/4WukqmWl.jpg
Occasionally we get items from EA that increase the bonus (an example is the balloons from the current pride event) but generally items have to be purchased with donuts. If you do not have any beach hideaways, then that would increase your bonus for each one by 20% (when fully upgraded, maximum of 5).
The hidden bonus depends on your progress in Springfield Heights. The 4th table in this thread lists hidden XP bonuses:
https://forums.ea.com/en/the-simpsons-tapped-out/discussion/81718/sh-tables/p1
Some players with large bonuses have been playing from the start, with lots of buildings and characters, but also spend a lot of time playing too.