Multi-vendor marketplaces, like ThemeForest, can be very successful. Chose a niche and create a vendor website for it. Your marketplace could be anything, from a platform for local artists to sell their work on, to an online digital product store. Once set up, invite people in that industry to sell their products on your site. You take a percentage of their profits when items sell.
If you have experience with marketing, SEO, or a knack for getting people excited about the products and services you use on a regular basis, think about refining your skills and putting them to work making money online as a small business marketing consultant in your region—especially if you can become a local SEO expert and can help local clients rank higher in their search results.
If you live in an area where Uber or Lyft operate, why not become a driver? If you're looking to make some short-term cash, you can definitely rake it in by working for one of these popular car-hire apps. As long as your vehicle fits within the specifications of their program, and you have a clean license, you could do this on the side, especially if you're in a crunch for cash.
If you offer freelance services or have a physical services business, then creating a blog is a must. On your blog you can write about the services you offer and how they will benefit your clients. Importantly you can add a ‘Services’ page, outlining the services you provide, what they include, and any other important information potential clients may need. This is an effective way to promote your services, generate leads, and increase your revenue.