Research individual companies in your desired niche: If possible, it’s always better to become an affiliate directly with a company (if they have an internal affiliate program), as no one else will be dipping into your commission rate. This is the preferred route for most of the prominent affiliate marketers, including Pat Flynn. Unfortunately, it’s also the most work, as you’ll have to do the research yourself to see who offers programs (they’re usually listed in the website footer).
As with online teaching, to maximize your chances of success as an online tutor, stick to subjects you know well. Use a reputable and high-visibility venue, structure your sessions sensibly, price your services in line with the market, follow scheduling best practices, and promote yourself enthusiastically (or choose a platform that does so on your behalf).