This video explains 6 key points to keep in mind while preparing notes. I have explained the ideas that helped me make my notes better during my GATE 2020 preparation.
I'm a proponent of short notes as I believe that if an aspirant is having plenty of time, he should better choose to go through the standard reference book again rather than noting everything that's there in his notebook.
Noting everything that the teacher says made sense in those days when students had to understand and keep everything in memory after attending a lecture once. Today, students have the option of going through video lectures again if they were not able to memorize in one go!