I am 30 years old and am retired. Previously, I made a modest salary as an Army officer. I own three duplexes and a quadplex in central Texas (10 rental units in all), and each of the properties provide me with net rental yields in excess of 15%. The last deal is actually an infinite return as my partner paid the down payment in return for a 50/50 split on a property that would otherwise provide a net rental yield of 18%. The above net rental yields also factor in an excellent property management team who manages my properties while I pursue other investment opportunities. To date, I have never interacted with any of my tenants nor have I ever had to personally deal with any maintenance issues.

If an investor puts $500,000 into a candy store with the agreement that the owners would pay the investor a percentage of earnings, that would be considered passive income as long as the investor does not participate in the operation of the business in any meaningful way other than placing the investment. The IRS states, however, that if the investor did help manage the company with the owners, the investor's income could be seen as active since the investor provided "material participation." 
Now, how do you do it? Building a passive income will require some work up front, but choosing a method that plays to your strengths will yield the most success, and it can even become a fun hobby! Have an aptitude for photography? License your photos to stock photography websites. Or maybe you’ve always wanted to invest? Learn how with a robo-advisor. No matter what your strengths are, we’ve gathered 35 ideas for different ways you can generate passive income and build your wealth.
If you have specialized knowledge in a certain topic, you can put together an online course to teach others. For example, if you have experience in real estate investing, you can create an online course “Real Estate Investing 101”. The benefit of an online course is that once you create the course material, you can sell it to as many people as you want.