Ebooks are one of my favorite sources of passive income. Now, you can do this the simple way and just publish it on Amazon's KDP. Or, you can go all out and build yourself a book funnel. Book funnels are powerful, but they won't be fully passive. For example, if you do a free-plus-shipping offer for your ebook (converting it into a physical book), you'll need to create some one-time offers (i.e. extra training) and up-sells (i.e. an audiobook). But, a book funnel can be very powerful. 

One of the most important assets you have is your credit score. By taking care of it and pursuing the steps to improve your credit score, a world of opportunity can open up for you. If you need a loan to buy that rental property or some quick funding through a business credit card, a good credit score will help you get approved so you can build passive income.
One of the best ways to build wealth is to get a handle on your finances by signing up with Personal Capital. They are a free online platform which aggregates all your financial accounts on their Dashboard so you can see where you can optimize. Before Personal Capital, I had to log into eight different systems to track 28 different accounts (brokerage, multiple banks, 401K, etc) to track my finances. Now, I can just log into Personal Capital to see how my stock accounts are doing, how my net worth is progressing, and where my spending is going.
Make sure your tenants understand that the rent is due in your PO box by a certain day. I recommend using a post office box to avoid tenants coming to your home. Understand how much you can legally charge for a late payment, usually a trivial amount like $15 after a grace period. Explain to new tenants your policy on the eviction process, i.e. when do you start the process when rent is late.
- HubPages.com is a content community for writers. Members (referred to as "Hubbers") are given their own sub-domain, where they can post content rich articles (known as Hubs). As a Hubber, you earn revenue primarily from Google AdSense (you need your own Adsense account) and other advertising vehicles such as, Kontera, and the eBay and Amazon Affiliate programs. There is a 60:40 revenue split and it’s achieved by alternating the code used in advertisements: Your code will be displayed 60% of the time, and HubPages' code 40%. Same as Squidoo, traffic dropped heavily due to Google's changes but the site is still wildly popular. Currently it’s one of the 500 most visited US sites on the Internet.
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.