Everyone knows something interesting for the others. You may be thinking that your knowledge is average and no one would be interested, but you are wrong! There is a potential audience out there that I’m sure would appreciate to learn what you know.
This is also applicable to programming skills for instance: the open-source world works very well, and it’s been a bunch of years now. Any programming language you know is valid to collaborate in any open-source project. Even fixing documentation will help.
So, back to teaching, this is what I enjoy the most. I have been teaching on-site in Barcelona from 2000 to 2006. My students were employees from private and public companies.
I remember a course about Linux development with C language, my students were engineers with many years of experience. By then I was only a student of computer science and that situation scared me a bit. I was thinking: “what if they ask me a difficult question?”. I spent so many nights studying so hard to cover any edge case susceptible to be asked. And yes, they asked difficult questions to answer by a college student, but I tried my best and they were satisfied, because they knew that those questions were ahead of the course boundaries. These things tend to happen with teaching, and since I was passionate about it, I was prepared.
That is an extreme case, but teaching can be as simple as opening a blog and write about what you know. You could also participate in a forum, in a question & answers site like StackOverflow answering questions about your topic, or even in social networks. Think of LinkedIn.
The easiest students are the beginners. You are probably struggling with your programming language daily, but maybe you are good with your operating system, say Linux or macOS for instance. Maybe you like to have a NAS in your home, configured with some interesting services to help you with some tasks. That would be interesting to teach too! You could prepare a series of videos about it and publish them in Youtube.
What would you get? You can get money, recognition, satisfaction… or all of them! If you want money you have to work hard, prepare a good course, interesting enough and capable to give your students the maximum knowledge on the topic. Then you could publish your course in a specialized platform like Udemy.
You could also get money in Youtube if your course stands out from the rest, but this is certainly more difficult, since you have to your own marketing.
Recognition is something that you can earn over the time, when you publish a bunch of very good courses, articles, collaborations… like anything else in life.
And finally satisfaction is something personal that you may achieve when seeing people enjoying your teaching. If they ask questions means that they are interested in the topic and they want to learn more.
By teaching what we know, we make the world a bit better.