Non-fiction e-books that educate your potential audience on specific topics like finance, online marketing, and business are going to make you more money than fiction books. Of course, there are always exceptions and you could write the next Harry Potter book, but if you want to create some residual income opportunities quickly, I would suggest you go for what sells first!

This is why we can retire in our 40s. we currently have four streams of income (my salary, husband salary, husband pension and our passive portfolio income which is outside of all our employer retirement accounts). our passive portfolio income is surpassed what most people are aiming for their retirement portfolios. And we don’t sell anything…this is just our dividend income annually. Passive income is the key to flexibility. No employer necessary.
Passive income investments can make an investor's life easier in many ways, particularly when a hands-off approach is preferred. The four options outlined here represent differing levels of diversification and risk. As with any investment, it's important to weigh the anticipated returns associated with a passive income opportunity against the potential for loss.
When a taxpayer records a loss on a passive activity, only passive activity profits can have their deductions offset instead of the income as a whole. It would be considered prudent for a person to ensure all the passive activities were classified that way so they can make the most of the tax deduction. These deductions are allocated for the next tax year and are applied in a reasonable manner that takes into account the next year's earnings or losses.

Another way to generate passive income is to invest and be a silent partner in a business. This is very risky, but with risk comes the potential for high returns. For example, several years ago both Lyft and Uber were looking for private investors to invest in their companies. Today, they are worth billions - but you as an investor would only reap that benefit if they go public via an IPO, or get acquired. So, it's risky.
Truebill is an app that helps you save money by identifying recurring subscriptions and other bills and helping you cut costs by negotiating better rates and fees. One of their partnerships is with Acradia Power, which has the potential to save you up to 30% on your electric bill. It searches for better power rates in areas where competition is allowed, and it locks in the better prices for you.
As you may have noticed, there is a common theme throughout all the ways the wealthy generate passive income.  All of them require you, in the beginning, to trade your time for money while building your passive income machine.  Eventually you will be able to leverage that time into exponential passive income while being able to work less and less.  The attitude being a willingness to take some risk, work hard, and create something of value.  If you put good in, you will get good out.  Wealthy people tend to choose this attitude more than others.
Given the growth in the sharing economy, your junk can start to pay for itself. For example, if you have some awesome vintage furniture inherited from your grandmother sitting in a storage unit, you can rent this out to photographers for their “styled shoots” which are becoming all the rage. If your furniture is more modern but you still can’t bear to get rid of it – perhaps a home stager will be interested.

Investing in bonds: Similarly, bonds are an attractive way to engage in passive income. Over a recent 45-year period, bonds funds, as measured by Vanguard Funds, returned 7.1%. Of course, there's no guarantee that investments in stocks or bonds will always work out well, investing in them is by far the surest way to generate money through passive income.

Wow! What an awesome list! My favorite is the stock photography because I love photography. I have had some success there, particularly with one photo I make some decent income from. I think the key with stock photography is finding a shot that is high demand. Then, find a new unique way to frame that shot. This is the reason my St. Louis Arch photo is a top 10 on both ShutterStock and iStockPhoto. Thanks for the awesome ideas above!