Fiverr is one of the biggest providers in the gig economy on the web and you can sell a wide variety of services and products through this medium. Do the research and find out what you can offer. However, keep in mind that like any other money-making task, it takes time to succeed here. And stellar reviews will help you generate more and more income over time.
Not only that, you will be able to evaluate business ideas much more intelligently once you've gone through this whole process. You will understand the fundamentals of keyword research & analysis, traffic & lead generation, social & affiliate marketing, monetization & conversion testing, and traffic analysis. These skills will help you immensely in ANY business you ever decide to start (online or not, passive or not).
Because you don't have to spend money on acquiring, storing, handling, or shipping products, Affiliate Marketing becomes a pure exercise of bringing traffic to your website and of trying different ways to convert this traffic into buyers. You can experiment with the design of your landing pages, test video product reviews against written reviews, and try Email Marketing.
Teaching and tutoring English as a second language is a great way to make money online, not to mention open some doors for you to travel the world if you'd like. While full ESL (English as a Second Language) accreditation is recommended, as long as you’re a native speaker and have the ability to teach, there are people in countries such as Hong Kong or the UAE who are willing to pay upwards of $25/hr for you to tutor them English via Skype. Check out Indeed, Learn4Good and Remote.co for remote english tutoring jobs or sign up on a specialized site like VerbalPlanet or Chegg Tutors.
Tools & Resources: I’ve written a pretty comprehensive guide on the best web design software that covers both free and premium software packages. If you’re serious about becoming a web designer, then I recommend purchasing the full Adobe Creative Cloud Suite. At $49.99 per month, this is probably a bargain considering what you can achieve with this set of tools.
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. 
Work remotely for a call center. Because many call center jobs are location independent, finding work in this field is an easy way to earn some money from home. Dozens of sites list job openings for call-center representatives, including Freelancer.com and SimplyHired.com. Meanwhile, you should check local job listings for openings and opportunities as well.
Do you see all of those articles, tutorials and guides all over the Internet? Somebody wrote every one of them! If you have decent writing ability (no, you don’t need a journalism degree!), and knowledge in a few specific topic areas, you can be one of those writers. It’s an opportunity to make money online and without ever leaving your home. It’s also the kind of venture that can start out as a small side business, but grow into a full-time career.
With YouTube´s “partner program”, You can make extreme numbers if you have a big amount viewers and subscribers. Together with YouTube, you will make a percentage of the ad revenue that comes from your videos. There are currently lots of people living of Youtube and the largest YouTuber “PewDiePie is the top-earning YouTube star on the planet-earning $12 million in the past year!
Infographics are currently an extremely popular type of media. An infographic showing information or data in an interesting and fun way can help engage an audience and generate numerous likes and shares. As infographics take more time to create than just simply uploading an image, busy website owners are prepared to pay for custom infographics. And don’t worry, an infographic can be created using simple design software such a Canva. So extensive graphic design skills are not necessary, just a creative eye.
Mechanical Turk is Amazon's take on micro-jobs. These are small miniscule-jobs that you can do for other people, which they call HITs, or Human Intelligence Tasks. These are super simple tasks that anyone can do. Some examples are listing off some URLs with certain kinds of images for one cent, or recording a few phrases with a microphone for 6 cents.
23. Affiliates – There are many affiliate networks, such as FlexOffers and CJ Affiliate that allow you to promote other people’s products and services. You simply put a link or a banner on your page and then you get a percentage if someone clicks through and buys the product/service. You’ll want to select products that are specifically within your blog’s category.This is an effective way to earn money once you have the traffic coming to your blog.
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.
Last but not least, you can also earn money online by building an online community, although the monetization strategies you can pursue will vary a lot depending on your goals. You can build a community with a blog, for example. You can also build an online forum and charge people for membership. You could even build up a Facebook group and use your influence there to sell and promote products.