Aside from earning money from jobs and fishing, and the likes, you can also earn some side cash by improving your apartment.
How it works is this - improve your apartment by expanding and furnishing (as well as regular cleaning) and you will be able to gain SoBucks for every visitor that visits your apartment. Simple, right?
There are a few things to keep in mind:
1. No Multiple Visits, meaning that if your friends enters your apartment multiple times a day, only the first time counts.
You can view your Apartment statistics by clicking on the Apartment Key icon in the icon bar:
2. It Resets Daily, so that friend can come the next day and it will count.
3. Amount earn is a combination of apartment wealth and apartment cleanliness
You will then be brought to an 'Apartment Management' page. Here, you will be able to view Today's and Yesterday's earnings, as well as earns per visitor and how many of your rooms are clean.
Notice that you WILL NOT earn any SoBucks if your apartment is not cleaned. It will give a warning on the Apartment Management page if that is the case.
How do you clean a room?
On your icon bar, you'll see a broom icon.
Clicking on that will bring your character into a sweeping animation. There will also be a percentage statistic on the lower right hand side of the screen.
Continue to click on the broom at various parts of your room to raise that percentage to a complete 100%.