Find a profitable niche. Starting with your interests, write down as many niche ideas as you can. Think about topics people might search online. Ideas include passions (like surfing or body building), fears (like spiders or speaking in front of crowds) and problems (like getting out of debt). Do keyword research to see it others are interested in the topic. Find out if a domain name is available that matches the keyword 100 percent. [7]
In Eric Reis’s The Lean Startup, a fantastic book about how today’s entrepreneurs and startup companies are approaching the way they create and innovate, Eric talks about how vital it is to use validated learning and scientific experimentation to be able to steer a company in the right direction. In other words, to use customer feedback and quantified data analysis (of real, non-vanity metrics) from a minimal viable product to make decisions and pivot a business one way or another.
More than half a billion products are sold on Amazon every month, making it an incredible opportunity to make money online. But, like everything else that involves making money online, you have to do quite a bit of work to earn it. One option on Amazon is to find products that are already made and buy and sell them at a discount. For example, you could research generic products such as clocks, keychains and mugs to attach to your brand. For an incredible deep dive on how to make extra money with this strategy, check out how digital marketer Neil Patel recently did this as a public experiment right here on his blog.
With $200,000 a year in passive income, I would have enough income to provide for a family of up to four in San Francisco, given we bought a modest home in 2014. Now that we have a son, I'm happy to say that $200,000 indeed does seem like enough, especially if we can win the public-school lottery to avoid paying $20,000 to $50,000 a year in private-school tuition.

Work in grocery delivery. Instacart is a company that will pay you to pick up grocery store orders in your spare time. The entire purchase and order takes place through the Instacart app, making it easy for you to pick up the groceries your customers wants and get paid. Like other food delivery jobs on this list, Instacart lets you earn a per-trip rate plus tips. Shipt is another service that will pay you to shop for groceries and deliver them to consumers in your area, so make sure to see if they’re available where you live.

If it’s not clear yet, information and expertise are two of the most consistent and lucrative ways to make extra money online. If you don’t like talking on the phone, you can sign up to get paid to answer professional questions on JustAnswer. There are thousands of questions being asked every month from people looking for help from lawyers, doctors, mechanics, vets, and more. To apply, you’ll need to supply your professional verification, resume, and a form of identification.

That said, lot's of people are making extra money by publishing their own books on Amazon.  For instance, my friend Bob published a few books on Amazon on how to make money blogging and has done very well.  The first book provided basic tips for a small price, but his next book, Pro-Blogging Secrets, is offered at a premium price and he also has an online course.
No matter how you earn your income, you may need to report it to the IRS at tax time, so keep good records and track expenses. And remember that you shouldn't let your part-time or gig work detract from any full-time or salaried position you already hold. Says Sullivan: "Make sure to be diligent with your time, so you are still able to do your full-time job while making deadlines for side hustles and freelance work."
If you’d prefer to skip the startup phase, you might want to buy a blog that’s already built and earning revenue. This is actually pretty easy to do as a lot of people start blogs, and then get bored with them. Getting a blog going is a labor-intensive process, and it’s not uncommon for people to give up before they’ve reached their full potential.

Get paid for your opinions. Taking surveys online can be a relatively quick way to earn enough to afford a few extras. Harris Poll Online, for example, awards points for the completion of online surveys, which can take between five and 25 minutes to fill out. Survey takers accumulate points and can redeem them for gift cards from retailers such as Amazon and Starbucks. Other online outfits that will pay you to take surveys include SurveyClub, Global Test Market and Swagbucks. There's no cost to sign up.

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.
2. Focus on income-producing assets. Internet growth stocks may be sexy, but they provide no income. To build a large enough passive-income stream to survive, you must invest in dividend-generating stocks, certificates of deposit, municipal bonds, government Treasury bonds, corporate bonds, and real estate. You're free to invest in non-income-producing assets for capital appreciation too. You just want to earn reliable income when the day comes to leave your job.

Once you’ve had children, many parents find themselves caught in the trap of needing to work but wanting to stay home with their kids. Creating your own parenting blog can not only be a way to make some money, but it can also help you connect with other parents and make sense of those crazy sleepless early parenting years (it does get easier don’t worry!)
When you lack the luxury of time, making money on or offline can seem like an impossible task. How are you supposed to do that when you're working at a life-sucking nine-to-five job? While the stability of full-time employment might allow most to sleep well at night, it doesn't empower your creative juices to search for new income-producing strategies.