Connecting Ideas
The Unix philosophy suggests that programs should do one thing and do it well and your notes should do the same.
A rule of thumb is to keep notes short enough and to fit on a single screen without scrolling (and you should break this rule when needed). When you are constrained, you are forced to think about the fundamentals of the idea you want to convey. This is the key idea of atomic notes.
However, I go further, notes should not just be atomic, they should also be modular. You should design your notes in such a way that you can easily move, link, and duplicate them in your knowledge system without any rewriting or refactoring. This modularity allows you to easily connect and reconnect notes together.
Progress is rarely made by brute-force thinking. Good ideas are rarely conjured from the ether. Progress is more often made by making connections.
Writers make connections between ideas. Engineers make connections between things. Business leaders make connections between people.
By connecting notes we expand our learning and understanding. By connecting ideas, we develop a framework to represent the data and facts of our respective areas of interest, enabling us to become experts in our field. All that's left then is to elaborate on our network of connected ideas in a meaningful way.