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, A List Apart, International Living, FundsforWriters, and Textbroker.
Don’t set a goal to write 3 blog posts a day… set a goal to write 1 blog post a week and make that post super helpful, long, and filled with information that is so valuable you will say “yeah, people will link to that.” 90% of my traffic/affiliate income comes from just 20 tutorials, many of which are 5+ years old. But I am constantly updating them to make the content better.
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.