Check if you need a model release. Photos of people can only be sold for commercial use if they've signed a 'model release' that gives you permission to use their image (children need a parent/guardian to sign). Without a release, these photos can still be sold for editorial use, as long as they were taken in a public place – eg, if you submitted a 'breaking news' shot with people in the background. If there's any doubt, always ask permission.
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.
If you’ve got a way with words and expertise in a niche, there are plenty of sites that will pay for articles and content you write. Think of the sites you read regularly. What can you contribute to them that would be interesting? Research your niche and then look for ways to pitch articles. Many sites will simply have a submission or contact link in the footer. To get started, check out my full guide to becoming a freelance writer on the side and then submit your articles to places like Instash, Listverse, TopTenz, A List Apart, International Living, FundsforWriters, and Textbroker.
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.
No matter what you do to make money online, promote it on your social media accounts. You have a base of people who are already interested in you and have a vested interest in your brand – why would you not want to take advantage of that? By promoting yourself and your projects on your social media accounts, you’re greatly increasing the chances of people actually giving you money in exchange for your goods and services. Stop being shy and get out there.