Open source devs: please, please add screenshots...
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....
Also please begin the Github page or whatever with a description of what the app is actually for or what it does. I know that sounds super obvious, but the number of times I've seen links that are like "I made this app from scratch for fun, let me know what you think!" and then you click through and the app is called Scrooblarr or something and it has no indication of what it actually does is... more than it should be.