​Udemy is an online platform that lets its user take video courses on a wide array of subjects. Instead of being a consumer on Udemy you can instead be a producer, create your own video course, and allow users to purchase it. This is a fantastic option if you are highly knowledgeable in a specific subject matter. This can also be a great way to turn traditional tutoring into a passive income stream!

​Affiliate marketing is the practice of partnering with a company (becoming their affiliate) to receive a commission on a product. This method of generating income works the best for those with blogs and websites. Even then, it takes a long time to build up before it becomes passive. If you want to get started with affiliate marketing check out this great list of affiliate marketing programs.

Good ranking FS, I’d have to agree with the rankings. And it looks like your portfolio covers five of the six! Some people consider real estate passive will others classify it as active. But every scenario is different, whether you are doing all the maintenance and managing yourself, or you are contracting out a lot of the work. Obviously it takes a lot more time and effort than purchasing a 36 month CD and “setting it and forgetting it.”
To save time and effort, a person can group two or more of their passive activities into one larger activity, provided they form an "appropriate economic unit." When a taxpayer does this, instead of having to provide material participation in multiple activities, they only have to provide it for the activity as a whole. In addition, if a person includes multiple activities into one group and has to dispose of one of those activities, they’ve only done away with part of a larger activity as opposed to all of a smaller one. 
We have decided to invest in 2 ETFs, a multi asset allocation ETF (Fixed Inc, alts and div paying equities) and a preferred stock ETF. This will cover almost 45 percent of our deficit. We will be extremely diversified, can access the markets at a very low cost and the investments are liquid. On this pool of $, we have no plans to invade principal unless the investment grows by 20 percent, which we think is unlikely given the characteristics of the investments.
Wouldn’t it be nice to earn money while not working? That money is called residual, or recurring, income. It's what can happen after you put a lot of time, effort and sometimes money into a job to continue to get paid for the work months or years after it's done. (Salary jobs are part of linear income. This income is directly related to the number of hours you work. If you work 40 hours, you get paid for 40 hours of work.) Once you set up your business to earn residual income, you continue to make money while doing other things – maybe even starting a new business to generate more residual income!
Residual income is the best model for money generation. Once you master and build up one avenue, you can devote your time and money into another avenue. Eventually you start reaping the benefits of multiple residual income avenues. Enabling you to have complete financial and time freedom. I recommend to all people to build these types of asset models as they can greatly improve their life.