I beg you, if you are a developer of an open source app or program - add screenshots of your app to the README file. When looking for the perfect app, I had to install dozens of them just to see what the user interface looked like and whether it suits me. This will allow users to decide if the app they choose will suit them… Please, don’t think about it, just do it…
If you’ve written a “usage” section that showcases more than one uselessly simple example that doesn’t even work in the project’s current state, you’re already far ahead of the average.
This is how I generally write documentation for my projects: https://tybalt.org