Unfortunately, it took a while for the real lessons to sink in. I was probably 20 or 21 when I read Rich Dad, Poor Dad the first time, which means I wasn’t exactly sure who I was yet. I knew I wanted to work hard and make money, but I wasn’t sure how. This made me a prime candidate for  multi-level marketing pitches, and the dream of “getting rich quick.”

One of the most appealing options, particularly for millennials, would be #12 on your list (create a Blog/Youtube channel). The videos can be about anything that interests you, from your daily makeup routine (with affiliate links to the products you use), recipes (what you eat each day) or as you mention, instructional videos (again with affiliate links to the products you use). Once you gain a large following and viewership, you can earn via Adsense on YouTube.
​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.
Managerial accounting defines residual income in a corporate setting as the amount of leftover operating profit after all costs of capital used to generate the revenues have been paid. It is also considered the company's net operating income or the amount of profit that exceed its required rate of return. Residual income is normally used to assess the performance of a capital investment, team, department or business unit.