I make mind maps of what ever topic I am learning / researching. (https://github.com/nikitavoloboev/my-notes-mindmaps#github-i...)

I then add it to to the main research (https://my.mindnode.com/83qmKgoATj8TyKzprzsPfoirxa2g9WmFGx3x...) mind map.

It's actually really easy to keep it up to date and it is very rewarding knowing that I can share my knowledge with other people.

I also wrote about my approach about mind mapping here (https://medium.com/@NikitaVoloboev/mind-map-everything-d2767...).