I run an Open Source workshop, where attendees get guided help finding and submitting PRs. So far almost 100 people have attended 4 workshops. Attendees have successfully contributed to countless projects in the NodeJS, Ruby and Python ecosystems.
I've personally contributed to dozens of '10K+ Star' GitHub projects across many languages. JS, Ruby, Shell, Go, etc. Also I've written plenty of examples & fixes on Mozilla's MDN site.
The secret is: next time you find something broken, fix it. Next time a README lacked sufficient examples, causing you to reach for a new google search... Go back and fix it once you find the missing piece!
Specifically, copy-and-paste it in the place that would have made your experience easier.
I'm talking about documentation, as it's a great place to start. It's low commitment, high impact.
For example, a single-line commit I landed in the React Router docs changed the default home page content - I didn't write a line of content, yet potentially helped thousands of devs. I simply helped connect the dots for future devs. This led to a few increasingly substantial contributions, and a shout-out from one of the projects co-creators on twitter.
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