IDA has invested more than $2 billion since 1991 to address the country’s infrastructure gap, partly through the Road Sector Development Program (RSDP). IDA helped build capacity and establish a dedicated road fund for financing maintenance. Working in partnership with other donors, including the European Commission, Germany, Japan, Nordic countries and the United Kingdom, IDA helped increase both the size and quality of Ethiopia’s road network from under 20,000 km in 1991 to over 100,000 km in 2015. Under the CPF, the World Bank continues supporting improvements in transport infrastructure and road connectivity to reduce travel times and improve connectivity between markets and secondary cities.
I know many people who are into a full-time Job, but they make it a point to write 2-3 blog articles every week, and now their blog is very popular among netizens, and they earn decent from the advertisements, sponsored articles. This again is not so easy as you have to learn some amount of SEO and SMO and should be regular with good and useful content.
I have not. While I am intrigued with the possibility of making online income, it seems to be less passive then how I want to spend my time. Regarding your blog / site, you have done quite well for yourself. However, you have to keep pumping out content or your site would eventually go out of business. That sounds like more of a commitment then I would want. Regarding your book sales, it is probably relatively passive now, but certainly was not when you were writing the book. Now if you love it, great. Just not for me.
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.

I like the way you have listed the ways to earn extra income and was quite surprise that you did not make mention of network marketing, which is a way to make extra income without quitting your regular, though most people view mlm as a pyramid scheme but the real pyramid scheme is a regular 9 to 5, because you can only have one president of a company at any given time and network marketing business model to promote product that can be used is really cheap to join and can offer a substantial extra income or what do you think?
How do you do this?  Well, try to get the highest paying job you can!  Ask for a raise!  Utilize services, such as, to see how your salary competes with others in your same job.  Some companies really force employees to leave to get a raise, and then come back for another raise.   This industry jumping promotional strategy is very common and could work.
5. Make sure you are properly diversified. Capital preservation is underrated. We saw a lost decade for tech stocks between 2000 and 2010 after the first dot-com bubble burst. It actually took 13 years for Nasdaq investors to get back to even. Investors in the Borsa Istanbul stock market index just gave up 10 years' worth of gains after they saw a plunge in their currency, partially due to increased tariffs by the US and a lack of confidence in the government. Your passive income needs to be properly diversified in order to take the hits.
Sell an eBook Online – 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.