I have some opinions…

1. Start from something you’re using (and like using). You’re both more likely to have opinions and more likely to be able to sustain contribution
2. Look at the project’s website/documentation/github readme/contributing.md and look for any sorts of recommendations for new contributors. Many projects will have suggested “newbie bugs”
3. Pick a bug and start working on it in a branch. Submit a PR. Be very open about your newbieness and willingness to take feedback. Actually be willing to take feedback. :) When I was maintaining ZURB Foundation, someone who would eventually be on our core team had over 100 back and forth comments on their first PR (it started out really bad, but he stuck with it and kept working on both the PR and his skills).
4. It doesn’t have to be technical bugs… you could work on the docs. Or improving the test suite. Both of these provide great value to the project and are good ways to learn about the code.

Meta note: When you’re considering a project, check out things like how often they’re merging 3rd party prs (look at the merged PR list vs closed/open and see if there’s good representation of a number of people). Also look for conversation in those PRs and in issues… is this a community that is welcoming to new members?

Great idea for a podcast, Ed! 👏

I love what @kball posted, so here’s a hearty +1 for all 4 of his points.