It depends on the exact nature of your work. I’m using Obsidian for personal and work, not design related but it does blend Zettelkasten, project files/folders, and meeting notes all in one vault. It works well, as long as I keep the three concerns relatively distinct. (I link between them as needed, but do keep the conceptual boundary between each of them)
One thing you can do (similar to what I do) is keep your project-related files in a /Projects folder and then have your Zettelkasten elsewhere containing principles. Using Andy Matuschak’s advice to write titles as positively-worded declarative or imperative phrases that capture the full idea contained in the note, you could write notes that cover principles that you find useful in your work.
Hypothetical example outline note with hypothetical note titles:
To tie a design together:
- [[Establish visual order through element alignment]]
- If the design feels off check the alignment of elements
- [[Repetition creates familiarity and flow throughout the design]]
- [[Relate elements together by placing them in close proximity to each other]]
To highlight important elements:
- [[Establish visual hierarchy to emphasize important messages]]
- Can be done through different size, different weight, use of borders, contrast, etc.
- [[Contrast leads the viewer’s eye, so consider it to highlight important elements]]
- [[Relate elements together by placing them in close proximity to each other]]
Etc.
And yes the last element is a single note linked twice in the same outline note in two different contexts.
You could obviously write your own principles that you see emerge from your work, capturing the design patterns and results that you find most useful over time. And create notes on those that you find are anti-patterns that should be avoided because they lead you into trouble later in your design.
You’ll notice too that what this amounts to is akin to being told write an ongoing series of mini-articles about your design process – which is pretty much exactly what a ZK is, and is why Ahrens advises writing in your ZK as if you were writing for someone else. (not that you have to be perfectly grammatically correct or have beautiful layout, but that it is written well enough to explain the concept to a new reader, including your future self – and this makes it relatively easy to turn the content into a series of articles on a variety of topics later if you want to do that)
Just a thought, hope it helps.