These were my first libraries.
I took the approach of promoting them as any other product. You have to "sell" your code. Even if it's 100% free.
In my opinion, the most important thing is DEMO. Just make a GIF where you showcase what your software does:
* 80% of engineers won't even bother to read the description
No one will spend their precious time trying to get through your code.
[0] https://github.com/kotartemiy/newscatcher Programmatically collect normalized news from (almost) any website.
[1] https://github.com/kotartemiy/pygooglenews If Google News had a Python library