In the 1940,Cornell Professor Walter Pauk developed a new note-taking system to give college students a better way to organize,condense,and intake knowledge.It’s proven as an incredibly effective learning tool.Here is the example, you can download it-

Notebook- Cornell System⬇️

Diagrams for better Understanding

I usually use diagrams, drawings for better understanding,co-relations,memorisation & easy recall.Have you tried.