When you are making notes for your slip box or Zettelkasten system always be asking good questions and try to make connections with other notes. Try to see what is missing.
Business biographies are written by the successful. The entrepreneurs who failed never get to write their book, their story. Can we learn more from them? Probably.
And the things that made the successful succeed may also have caused the failures to occur. Be careful about correlation and coincidence and causation.
Forget about thinking outside the box; think inside the box.
Thinking inside the box
Having restrictions can be liberating and can foster more productivity and progress.
Having too much choice is not necessarily a good thing as you may spend too much time, energy and creativity making the choice rather than thinking creatively within the slip box collection of notes.