Disclaimer: the game is (as of writing this guide) quite buggy. So if you're having problems with this,
it could be that the game is bugged. This guide lays out the rules when the game is working as intended.

First, the basics
There are six rackets:

- Hotel
- Safehouse
- Brewery
- Speakeasy
- Casino
- Brothel

With regard to the synergy bonus, the hotel and the safehouse are disregarded.
So to make it simpler: bonuswise you only have to think about these four :

- Brewery
- Speakeasy
- Casino
- Brothel

The synergies are:
Five of a kind - five of the same type - 12,5%
Straight - one of each type - 10%
Full House - three of one type, two of another - 7,5%
Three of kind - three of one type. - 5%
Two pair - two of one type , two of another - 2,5%



First rule:
A single instance of a racket is only counted once toward a synergy bonus.

For example: If you want the ' Straight' (one of each) and a 'Three of a kind'(Three of the same type) you'll need 4 + 3 = 7 rackets in your area.

Second rule:
When a combination of rackets could count as one bonus or another, it will count as the one with the highest percentage.

For example: if you have the 'three of a kind' bonus with three brothels and afterwards you want the Full House(3 of one type, 2 of another), and you buy three more brothels and two Speakeasies, you will lose your 'three of a kind' and you have only gotten the 'five of a kind' bonus, and no 'Full House.'

This can become confusing very quick, because once the highest possible bonus is chosen, it doesn't seem to update if other combinations are possible.
This can can mess up your intentions, if you build a specific racket for a specific bonus.
So to make it easier on yourself: start with the largest bonus and work your way down.

Lets start with a fresh neighborhood:



We start with getting the highest percentage bonus which is Five of a kind.
In this example I build five speakeasies, but you can choose any type you want.

Once we have done this, we will also build a hotel so we can see the names of the rackets that count toward the bonus:



I named my rackets in a way so I can recognize for what synergy they where meant, this is not necessary of course, however I would recommend naming your rackets to something you recognize.

So, we go to the next bonus: Straight.
For a straight you always have to build a brewery, speakeasy, brothel, and casino.



Next one: Full House.
In this example I build two breweries and three brothels:



Next one: Three of a kind and Two pair
I build this one in one go.
for Three of kind I build three brothels
and for two pair I build two speakesies and two casino's:





And just like that, we have all the synergies.

It's possible to make no mistakes and still lose, that's not weakness; that's life.
Or bugs, possibly bugs.

One thing I encountered when I first tried this guide was one racket that never counted toward a bonus. It was as if it didn't really exist in the game. So I had five speakeasies, but only a three of a kind:



Because I had numbered my rackets I could find out which one it was and disregard it. But this can confuse like hell.

Another weird thing was when I sold rackets to start of over and make the names make sense, suddenly my five of a kind was activated by: three speakeasies and two brothels...which should not happen. - I did not grab a screenshot of this.

So be aware that bugs can mess up your game a bit.
If you find bugs, please consider filing a bug report.