Hi Fred,
great idea. I am happy to share mine.
The outline is based on two major pillars.
- Areas. Categorizes notes on why I keep them (because they contribute to one of my projects, commitments or interests)
- Layers. Categorizes notes based on their types (whether they refer to an event in time, an external source or an original thought or insight)
Also do have a read on how I use the supernotes feature set in general, where I particularly explain my approach to building a hierarchy.