Well if you have some trick to sudy very well you could put it to help persons who don't have and want to have.
It can be just to retain many things for our mind, before a test or anything else !!
When you write with a red pen it's good to retain in your memory what you want to study or a thing to not forget. This colour is better than other and when you write in general you retain more too.
So a trick it's to write with a red pen !!
Hello excuse me..I do not under stand .? Would you repead .?