This is a great point that even experienced engineers sometimes forget: Every time you reduce friction to contributing (including psychological barriers) by 50% you more than double the number of contributions. Product managers routinely analyze conversion funnels to improve revenue. But open source project maintainers can forget to analyze their “contribution funnel” to improve their software.
Another aspect to encouraging contribution is giving credit. I’ve been experimenting with an AUTHORS.md file (example from a project of my own) that not only lists contributions of everyone but also calls out key roles. Would be great to brainstorm ways to improve that process, too.