I'd say the most important lesson I learned was that 90% of the people out there teaching and selling IM info products or training haven't got a clue about what they are doing. In most cases they got lucky with some technique or strategy and so they think they are brilliant and the first thing they do is package it up as the new shinny object for all the other IM suckers top buy. They usually don't even have enough experience or insight to even understand the "real" reason why they had some success and so when they teach it they often leave out the parts that actually led to their success. This is why it is often so hard for anyone to repeat their success.
Last but not least, you can also earn money online by building an online community, although the monetization strategies you can pursue will vary a lot depending on your goals. You can build a community with a blog, for example. You can also build an online forum and charge people for membership. You could even build up a Facebook group and use your influence there to sell and promote products.
Your niche doesn't necessarily need to be an area you're already an expert in. You can also choose a specialized area which you're enthusiastic or interested in learning more about.Think of Oprah, she doesn't market herself as an expert, but she frequently brings other experts on her show. You can do the same in your niche, by giving other experts a platform to promote themselves in exchange for content creation.
make extra money online