Life is really uncertain in many ways. There is no simple formula to earn income. Learning the formula is easy, execution is difficult. There are many formulas define on the internet to earn money online like youtube, blogs, products. but... not every YouTuber, blogger, product maker get success. It's all depends on what value you are giving to people. To make something valuable, you have to spend your time, and to generate actual sales you have to create trust.
So, from where trust is earned? For example, If you meet a person for the first time, you have no trust. You can earn trust points by a conversation in his/her language. Same as If you give your customer what he wants, he/she will be your future customer and might give a positive review. People like to listen to reviews and make their decision accordingly.
Recently, I publish a book on Gumroad. The lesson shared is based on the experience I have in the past year.
If you have any related experience, I would love to hear from you.