I think ECS is a new enough architecture that the patterns are still very much folk lore.
I think a lot of the way I try and structure my Bevy apps comes down to trying to separate the rendering from my game logic. Its very easy to confuse the two responsibilities.
Coming from the web and Ruby I find the lack of automated testing and TDD to be foreign to me. So I've been trying to figure out patterns that make my games easier to test. Hoping to write about it soon.
Check out the new Bevy Scene Notation: https://taintedcoders.com/bevy/bsn