You can select any of the above-mentioned, based on your interest, skill, and capability to generate a second income source. However, these are just to name a few, there exist multiple ways to generate a secondary income channel. You just need to identify the right one, which suits you the best. Remember there is no shortcut to success and you need to work hard to be successful and rich in the long run!
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.
The legendary investor, Warren Buffett rightly said that if you cannot create a second source of income by the age of 45, then you have really done injustice to yourself. If you are in business or if you are an independent consultant there are multiple streams that you can consider. But what if you are employed and your existing contract does not allow you to take up other work? Also, your pressures at your workplace may be tight enough to leave you with little spare time to worry about how to create a second stream of income. That is when you have to make money work hard for you. Let us look at two such approaches.
Infectious diseases continue to blight the lives of the poor across the world. An estimated 40 million people are living with HIV/AIDS, with 3 million deaths in 2004. Every year there are 350–500 million cases of malaria, with 1 million fatalities: Africa accounts for 90 percent of malarial deaths and African children account for over 80 percent of malaria victims worldwide.Source 9

First: I understand why you would say that such investments are restricted to only accredited investors, because generally, that’s true. There are means, under federal securities regulations and Blue Sky laws in each state, to sell interests to non-accredited investors – but usually those means are so heavily regulated and involve disclosures so similar to cumbersome registration requirements that it is not worth it for the seller to offer to non-accredited investors.
If you have a spare bedroom, you can find a roommate or list the space on AirBnB for travelers. Having a roommate is the more passive of the two, as being an Airbnb host will require more work in the form of turning over the room between stays. This is a super painless way to earn $500 to $1,000 a month without much effort – you may even be able to cover your mortgage payment with this extra income!
If you need cash flow, and the dividend doesn’t meet your needs, sell a little appreciated stock. (or keep a CD ladder rolling and leave your stock alone). At the risk of repeating myself, whether you take cash out of your portfolio in the form of “rent”, dividend, interest, cap gain, laddered CD…., etc. The arithmetic doesn’t change. You are still taking cash out of your portfolio. I’m just pointing out that we shouldn’t let the tail wag the dog. IOW, the primary goal is to grow the long term value of your portfolio, after tax. Period. All other goals are secondary.

To these human costs can be added the massive economic waste associated with the water and sanitation deficit.… The costs associated with health spending, productivity losses and labour diversions … are greatest in some of the poorest countries. Sub-Saharan Africa loses about 5% of GDP, or some $28.4 billion annually, a figure that exceeds total aid flows and debt relief to the region in 2003.Source 10
India's reliance on external assistance and concessional debt has decreased since liberalisation of the economy, and the debt service ratio decreased from 35.3% in 1990–91 to 4.4% in 2008–09.[293] In India, external commercial borrowings (ECBs), or commercial loans from non-resident lenders, are being permitted by the government for providing an additional source of funds to Indian corporates. The Ministry of Finance monitors and regulates them through ECB policy guidelines issued by the Reserve Bank of India (RBI) under the Foreign Exchange Management Act of 1999.[294] India's foreign exchange reserves have steadily risen from $5.8 billion in March 1991 to $426 billion in April 2018.[295] In 2012, the United Kingdom announced an end to all financial aid to India, citing the growth and robustness of Indian economy.[296][297]
This equation implies two things. First buying one more unit of good x implies buying {\displaystyle {\frac {P_{x}}{P_{y}}}} less units of good y. So, {\displaystyle {\frac {P_{x}}{P_{y}}}} is the relative price of a unit of x as to the number of units given up in y. Second, if the price of x falls for a fixed {\displaystyle Y} , then its relative price falls. The usual hypothesis is that the quantity demanded of x would increase at the lower price, the law of demand. The generalization to more than two goods consists of modelling y as a composite good.

Starting in 2012,[clarification needed] India entered a period of reduced growth, which slowed to 5.6%. Other economic problems also became apparent: a plunging Indian rupee, a persistent high current account deficit and slow industrial growth. Hit by the US Federal Reserve's decision to taper quantitative easing, foreign investors began rapidly pulling money out of India – though this reversed with the stock market approaching its all-time high and the current account deficit narrowing substantially.[citation needed]

Leveraging the internet to create, connect, and sell is something every creative person should attempt to do. The only risk is lost time and a wounded ego. You can start a site like mine for as little as $2.95 a month with Bluehost and go from there. They give you a free domain name for a year. Forget all the add-ons. Not a day goes by that I’m not grateful for my site.
I just graduated college in May and was fortunate enough to secure an entry level consulting position that pays 55k/yr (a little less than ~35k after 401K, other benefits, and the lovely taxes that government bestows upon us). I started from “scratch” with my finances and have ~$2.3k in an online savings account. Since starting work a couple of weeks ago, I’ve had an aggressive savings plan (saving around ~40-50% of my monthly income). However, I’m going to become even more aggressive and live off 1 paycheck a month (and save the other paycheck) like you have suggested in many of your blog posts.
The retail industry, excluding wholesale, contributed $482 billion (22% of GDP) and employed 249.94 million people (57% of the workforce) in 2016. The industry is the second largest employer in India, after agriculture.[153] The Indian retail market is estimated to be US$600 billion and one of the top-five retail markets in the world by economic value. India has one of the fastest-growing retail markets in the world,[243][244] and is projected to reach $1.3 trillion by 2020.[245][246]
Lots of good insights here. I’ve just recently gotten my own website for making online income. Also gotten a website for my fledgling voice over business. There’s a lot to learn when it comes to making passive income online, especially if you’re not financially savy, this is a very helpful blog in that regard, with all the useful tools and reference materials, it certainly removes a lot of guesswork.
Some scholars have come to the conclusion that material progress and prosperity, as manifested in continuous income growth at both the individual and the national level, provide the indispensable foundation for sustaining any kind of morality. This argument was explicitly given by Adam Smith in his Theory of Moral Sentiments[citation needed], and has more recently been developed by Harvard economist Benjamin Friedman in his book The Moral Consequences of Economic Growth.[citation needed]
This can be a little easier said than done, but if you have a large social media following, you can definitely earn money promoting a product or advertising for a company. You can even combine this with different marketing campaigns if you are an influencer and have your own blog (advertisement + affiliate income). This is how many bloggers make money! Again, it is not 100% passive but once set up correctly and then scaled, can be surprisingly lucrative.
Capital growth in your portfolio can offset the eroding effect of inflation.  But any capital gains that exceed the overall inflationary effect can be drawn off to augment your portfolio income.  Of course, you must first generate those gains by making thoughtful investment selections.  While allowing strongly growing assets to keep doing that, it is prudent not to allow them to become a dangerously large part of your portfolio lest they go off the boil.  So if you selectively trim profitable positions along the way, you can boost your income.