But don't make the mistake of thinking this will be a passive source of income—you're on call whenever you have a guest and you'll always need to keep the place clean for incoming visitors. On top of just renting on Airbnb, consider offering your guests paid add-ons, like Lauren Gheysens', Royal Day Out in London, England—where she gives visitors a local's only tour of the city, complete with bespoke 18th century costumes.
If you're serious about making money online, start a blog. Blogging is one of the easiest and most sustainable income sources. As long as the blog is setup the right way, in the right niche, with the right content targeted at the right audience, and the offer is complementary to the content, you could make a tremendous amount of passive income from a blog.
I may as well start with something I know well. When I started out as a freelance writer 20 years ago, things were very different. I wrote mostly for magazines, and I had to rely on snail mail to send out drafts and queries. I’d wait weeks for a response from my editors. Not many people had the patience for it, and few stuck around long enough to ever start earning a real income from it.
Better yet, you can even upload your own book to one of the world’s largest book sellers: Amazon. With Amazon self-publishing, you set the price, retain the rights to your book, and get access to Amazon’s massive audience. For every sale, you keep 70% with Amazon taking the remainder as a fee. If you want to get started, check out Tara Gentile on CreativeLive as she shows you how to use your existing body of work to write an eBook within the next week. Who knows, you might just write one of the best business books of this year!
Work Space. When acting as a consultant, the probability is high that clients will be visiting your home office. Therefore, you need to have a neat, professional home office that is welcoming to guests. Try to locate your work space in a quiet, even secluded, area of the house. A converted garage space with its own entrance works well, giving you a private space for work and adding to your credibility.
My 10-year-old son brought home a book from our park’s free library box. It was a biology textbook – teachers edition. He said it looked interesting and hey, it was free (having no idea you could sell it). I scanned it in my Amazon seller app and realized it was worth around $150. He was so excited. We listed it for sale for $130 and it sold! Going to tell him, he just made $130!
Medium is an online community where anyone can post articles and essays and get them in front of their audience of millions of monthly readers. While it can be a great place to build your audience for your own blog or find customers for your consulting business, with Medium’s new Partner Program, you can now make money online whenever someone reads your articles. Register for free and you can choose whether your articles are freely available or only readable by those people paying $5/month for a premium Medium membership. You’ll make money based on the amount of people who read and engage with your posts each month.
Now, it’s time to start creating and uploading content. Make sure you’re using a high-enough quality camera (most smartphones will work but I’d suggest at least having a tripod so your footage isn’t shaky), but don’t worry about being perfect at first. The beauty of YouTube is that you can continue to test out different content and styles as you find what works for you. Instead, stick to a regular schedule to build up your subscriber base.
Upwork: This website offers a great marketplace for selling just about any professional service. You don't need a merchant account, website of your own or anything else for that matter. All you need to do is be able to provide a high-quality service at a reasonable price. But be informed, you will have to compete with many others that are constantly bidding on open jobs.
5. Fiverr – Fiverr is a great place to make a few bucks or spend a few bucks if you need some of the services people offer. Basically, everything is $5. You either pay $5 or charge $5. They call them “gigs.” You can offer your services however you choose. If you sell art and you’re fine selling pieces for $5 each, that’s a gig. If you’re a graphic designer and you want to offer your services for $10/hour, simply offer a 30 minute gig. If they need two hours of graphic design, they pay you $20, or $10/hour by buying four gigs.
Double check yourself, before you double wreck yourself. Make sure everything you send to a company, whether a résumé, an email or a portfolio, is good to go. Double check your grammar and wording, and for God’s sake use spell check! This is especially important when it comes to the company’s name. Don’t spell their name wrong and be sure to type it how they type it (e.g. Problogger, not Pro Blogger).
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.
Test websites. Remote usability testing means getting paid to navigate a website for the first time and giving feedback to the website owner. Most tests take approximately 15 minutes, and you can get paid up to $10 for each test. A test involves performing a scenario on the client’s website and recording yourself doing it. For example, you might be asked to go through the process of selecting and purchasing an item on a retailer’s website.
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. 
And while it will take time to build up a big-enough audience to attract advertisers and other ways to make extra income from your podcast, the opportunity is there. John Lee Dumas interviews entrepreneurs seven days a week for his podcast Entrepreneur on Fire and now makes more than $200,000 a month from it. In fact, John publishes all his income online and showed that he’s made almost $13 million since launching in 2012.
Find a profitable niche: We’ve talked about this a lot. But, where are you most comfortable. What niche do your skills, values, and interests intersect? Do you have 10 years of experience as a technical writer? Do you have long-standing PR relationships that’ll be invaluable in helping startups launch a successful crowdfunding campaign? Determine what makes your value unique, and lean heavily on showcasing that strength to your potential clients.
If you've developed valuable skill sets or picked up certifications within your industry over the years, offering your consulting services to local business owners can be a lucrative way to make money online. Whether you're an expert marketer, business strategist, or manufacturing aficionado, there's likely a local business owner who's willing to pay you to help them solve an issue with their company. Start with this 18-step checklist to becoming a local business consultant from Karyn Greenstreet and then use my guide to crafting an effective cold email to convince them to hire you.
Now, it’s time to plan out your show. If you’re doing an interview-style show, you’ll now want to start getting some guests involved. You can use your existing social network to reach out to people you already know or are connected with on Twitter or Facebook. You can also head to Medium or Amazon to find authors or experts on topics specific to your niche.
If you love to travel and find yourself randomly searching for airfare sales or browsing Lonely Planet, why not carve out a niche for yourself as a private travel agent? My friend, Mark Jackson did just that, making extra money online with his travel consulting side business. Start with word of mouth recommendations from friends who know they can count on you for the cheapest flights, and then move on and create a Facebook or LinkedIn group to invite people who want to stay on top of the latest deals. Eventually you could spin this into a full-time consultancy teaching people how to make their dream trip a reality.
Be professional. When you submit a résumé, don’t type it in ALL CAPS and please don’t avoid the caps lock like the plague. Know how to use it without looking incompetent. Write in complete sentences with proper grammar. Of course, there will be exceptions, but even with the exceptions, you must keep it professional. You’re building their view of you.