For the last few years, I've been trying to find a topic to actually work on to develop a side project. I had quite a few ideas, but always got stuck on the "find people and understand their needs part", because I did not know people in the domain to talk to, nor could I find those people online.
You need a way to get people to discover you. If you don't produce anything, they will not ask any questions that can guide you towards what they need.
The first step in finding people to talk to in a field is to put yourself out there. As long as you can find one person to talk with, you will be making progress.
It might take a while to get there, and maybe what you'll write will be of use to no one yet, but with even a single question, you can start refining what your goal is.
Keep in mind what you like to do too. You might get questions about a topic that you don't actually care about. You can pursue them, but remember that not being interested in the topic will make it harder to work on.
Don't start with trying to find a niche. Just write about what you're interested in, what you want to teach and learn, and keep your eyes and ears open about a problem to solve.
Make sure to actually share what you write in relevant places, then be patient. There is no shortcut for this. You have to learn how to write well enough, then just keep going.
Don't start by trying to be the person known for something specific. The same way that a lot of startup pivot before they hit gold, your identity will need to pivot to reach something that resonates with other people. You will be know as someone specific, and you should try some of those identites out, but do so once you have a better understanding of your audience, not when you're just starting out.
TL;DR
- Put yourself out there, on topics that you like
- Listen to what people have to say
- Identify a problem to solve
- Write about this problem more specifically
- Refine your focus with what people have to say about it