Some things we learned in the first few months of using React (2017).
Note: This document might not be easy for complete beginners. It was originally written for someone who already knew React fairly well, and wanted some suggested talking points for a presentation they were planning to give to beginners. I have added some examples over time, but there may be room for more.
Also note: This document was written before React hooks, when we were using ES6 classes for components. Some of the advice (especially the earlier sections, and some of the error messages) does not really apply when using hooks.
Hooks have a number of new and different gotchas, deserving of their own document!