4. Affiliate marketing: Getting paid to tell people what you like and showing them where to get it. As a Dad, I tried 3 high chairs before finding the “Bumbo.” Now if I blog about the Bumbo and link to it to my Amazon account, and someone buys it, I can earn a commission. This is also a great way to build money over time, but it requires new content, staying top of mind and driving lots of traffic.
​Self Publishing is mainstream today. When you purchase an eBook off of Amazon there’s a pretty good chance you’re buying a self-published book. Self-publishing is also ridiculously easy. I tried this a few years ago and couldn’t believe how simple the process was. To self-publish a book you’ll first need to write and edit it, create a cover, and then upload to a program such as Amazon’s Kindle Direct Publishing. Don’t expect instant success though. There will need to be a lot of upfront marketing before you can turn this into a passive income stream.
My esteemed marketing colleagues initially balked at the idea of creating products that generate royalties, so I can understand how creating something from nothing might be daunting for those who aren’t even in creative roles. However, realize there is this enormous world out there of photographers, bloggers, artists, and podcasters who are making a passive income thanks to the Internet.

The doctor or lawyer, for instance, could use her or his income to invest in a medical start-up or buy shares of medical companies he understands such as Johnson & Johnson. Over time, the nature of compounding, dollar cost averaging, and reinvesting dividends can result in her or his portfolio generating substantial passive income. The downside is that it can take decades to achieve enough to truly improve your standard of living. However, it is still the surest path to wealth based on the historical performance of business ownership and stocks.

Or you could do joint ventures/strategic alliances for your business or for other businesses and make residual cash flow for $0 investment.. that’s what I do lol. No money, no risk, little time, 20+ years working from home. Just connect companies and take a %, use the Internet to do it locally or globally, be the intermediary & connect companies…. ;-)
If you can max out your 401k or max out your IRA and then save an additional 20%+ of your after-tax, after-retirement contribution, good things really start to happen. If one is looking for earlier financial independence, such as retiring in their 40s or early 50s, it may be a good idea to skew towards more after-tax savings and investments given one has to wait until 59.5 to withdraw from their 401k or IRA penalty-free.
Active income, on the other hand, involves earning money in exchange for a service. It could be a salary, an hourly wage, commissions, or tips. It’s essentially a trade of your time for a fixed dollar amount. Most people choose to live this way, and there’s nothing inherently wrong with that, as long as you understand that there will be a limit to how much money you can realistically earn.
I’m a 45 year old business owner who also has focussed on diversifying my income streams. I have a short term vacation rental in Florida that I bought for $390k in 2012 and net rental income for the last three years has been growing steadily. 2015 I am at $70k gross right now but should end up at $80-85k with net around $45k plus we use the place about 35 nights a year.
I have to agree. Our Duplex cost us 200k initially in 1998. Over time and completely refurbishing the property with historically appropriate sensitivity, we invested another 200k or so. We just had a realtor advise us we could ask 700k for it today. It nets us 30k annually after taxes, insurance and maintenance. We still have a loan on it which I have not taken into account, that will be paid off within 5 years if we keep it. My mental drama now is, while I am quite giddy over the prospect of earning a tidy sum of profit if I sell, what then would I do to equal the ROI and monthly income this thing generates? Rents are low, they should be 4k a month and will only go up. Tempted to keep it and not sell. And while I do have some stocks, I basically suck at them. I am much better at doing properties.

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. 
In equity valuation, residual income represents an economic earnings stream and valuation method for estimating the intrinsic value of a company's common stock. The residual income valuation model values a company as the sum of book value and the present value of expected future residual income. Residual income attempts to measure economic profit, which is the profit remaining after the deduction of opportunity costs for all sources of capital.