It took me a while to learn this. In college however I found I would read something and think, "Yeah, I totally understand this." and then need it later to find I didn't really understand it at all.
For me taking notes is a big part of it. For scientific papers reading the cites and then re-reading the paper helps cement things. For fiction I just seem to remember them and that makes re-reading kind of irritating/boring so not as keen on re-reading those.
But as the article touches on, for me it is the "why" sometimes that is key. Mathematics rarely sticks in my head unless I have a specific application for which the math is useful.
For me taking notes is a big part of it. For scientific papers reading the cites and then re-reading the paper helps cement things. For fiction I just seem to remember them and that makes re-reading kind of irritating/boring so not as keen on re-reading those.
But as the article touches on, for me it is the "why" sometimes that is key. Mathematics rarely sticks in my head unless I have a specific application for which the math is useful.