I started out by selling ebooks on eBay, which went very well until the platform banned the sale of non-physical goods. Genius move!
I then got a job working for a t-shirt printing shop in my town. I re-built their website so that it made a lot of sales and they became an overnight success. I then went into the t-shirt printing business for myself, in a different town. My website soon outperformed bricks & mortar shop sales, and I left the UK to live in Budapest, Hungary where I enjoyed a "10 minute workweek" lifestyle (Tim Ferriss would be proud) earning a considerable income and partying like a badass.
Then one day, around 2 years ago, Google did a thing and sent my website from page 1 to page 7-8 overnight. No warning, no explanation. Turned out that their algorithm detected "doorway pages" on my site (no such thing existed on my site, so their machine made a mistake). I appealed, I received an automated response and my search ranking wasn't re-instated. I had to close the business, all of my staff lost their jobs, and I became broke and homeless.
However, in the meantime I was learning about an area of interest that really appealed to myself, that of attracting women. At first, I went down the whole "pickup artist" route, and although I had some considerable success with that, I found it fake and unfulfilling. I learned a lot about myself that time and came to understand man-to-woman interactions in a whole new way.
I started coaching. I taught men how to develop their self-esteem and social skills so that they could bring women into their lives in a very natural way, without using any gimmicks, tricks or manipulation tactics. Then, a year later, I started to blog on this subject.
I created an ebook which I sell for $10 and immediately began to sell a lot of copies. I now write roughly 1-2 blog posts per week. I have 50 posts on my blog already, and I've sold multiple live coaching courses as a result of people finding my blog via google and/or related facebook groups.
It's a business model that works and I urge anybody who is wondering where to begin with this whole "making money online" thing to start a blog. You don't even need to be an expert in any particular topic.
For example, you could decide one day that you're going to be the "Free Range Chicken King". Start keeping chickens, and write about your experiences. Experiment with different feeds for the chickens, and write about that. Build your own chicken coop/house, whatever it's called that they live in, and write about how you did that. Find "chicken keeping hacks" that make things easier. Build a following. Lots of photos and good quality content that other chicken-keeping enthusiasts will be interested in. Egg recipes. Hey, even chicken recipes!
In time, you'll have enough knowledge to write an ebook. Doesn't have to be a huge one. "How to start keeping happy chickens, for beginners".
Charge $10 for it so that everybody can afford it. Post links to your best blog posts in related facebook groups. Post photos on pinterest, instagram, facebook, twitter. Get people interested in the idea of keeping chickens for the first time.
You'll make sales.
Apply this to any niche. As long as it's something that helps people and enriches their lives, you'll find success.