I wholeheartedly endorse the guidelines that Kent C. Dodds and Sarah Drasner lay out in this post. From "Saying thank you for the project before making an inquiry about a new feature or filing a bug is usually appreciated" to "Don’t close a PR from an active contributor and reimplement the same thing yourself," this is a concise compendium of rules everyone involved in open source should take to heart. (And yes, I've been guilty of some of these in the past and have seen the fallout, so my agreement with them has been earned through experience.)