Some projects try to make this easy. Check out this list / tag: https://github.com/topics/good-first-issue
People who know the code can quickly determine if an issue will be easy. Some things that may seem easy will be difficult, so as an outsider it's hard to guess. Working on issues tagged good-first-issue is the safest bet that the issue won't be overly complex to solve and that the maintainers are willing to work with new contributors.
Needing to turn off Mulvad for Netflix and other services was the deal breaker for me. Otherwise loved it.