I recently released django_migration_testcase. This isn't the first time that I've released a Python package - see flask_table - but it is the most complicated. And, specifically, complicated enough that it had several serious bugs when I first put it on GitHub.

After opening up the code, and other people being able to poke about with it I fixed two things that were downright broken - including the installation from pip and PyPI just not working - and questions about how to use it. While the code bugs could have been found by me, the documentation and usability bugs would have virtually impossible for me to find. It's so hard to identify which parts of your project are unclear or easy to use incorrectly.

For this reason, focusing on the hurdles to new users for your project is the best place to spend time, because the more you do it, the more it is done for you. And if you neglect it, you're pulling up the ladder stopping it from happening at all.