Sir can you recommend any method (apart from replay training ) to study classical games so that we can remember it for a long time
Good way to work through games.
The next question is should you take notes / diagrams to return to, or just keep going through games.
Possibly could do with an article on discovering why your moves were weaker (I work with an engine if there wasn't analysis to flick between my and the computer's lines until I understand the difference). This also is for analysing own games - such as in my post Why do we lose.
Also I think there may be benefit in recording (using free sound capture software) your thinking out loud so that you can better understand how you came to a conclusion and what you missed. As mentioned this could be interesting to compare between players to learn how others think to see your own blindspots. Perhaps this video's method is the way to carry that out.