From my failed attempt, I remember that
- Students had to find a project matching their interests/skills and start contributing early.
- We used to talk about staying away from some projects with a low supply of students applying (or lurking in the GitHub/BitBucket issues) because of the complexity required for the projects.
Both of these acted as a creative filter for projects and landed them good students/contributors, but it completely goes away with AI being able to do that at scale.