Core principals of Linus need to be written and followed.

1. Don’t break userspace!
2. Quality over quantity. No AI-slop in the GD kernel please… Kernel development underpins the entire Internet, medical devices, like all of the shit that actually matters out there.
3. Follow the established design patterns so that others can follow/review your pull reqs easily and quickly.
4. Socialize bigger changes early and often. Test extensively with distros who run bleeding edge releases.
5. Only be a dick when people ignore/break rules 1-4… and when discussing Nvidia.

Other than that, to me, the core rule of Linux is keep you code/app/service simple and atomic. Make sure that your widget talks/plays nicely with the OS components that it interacts with and that it can be easily swapped out for another analogue should you or all of the maintainers get hit by a bus.