how does self vod review work?

i don’t understand how people can look at their games and see what they are doing wrong themself because they are the one making the mistake but now they know it’s wrong?

i look at my games and the “mistakes” i make seem like good plays to me even though i know they are wrong but i dont know HOW they are wrong so i dont understand how to improve from it

what im asking is how tf do ppl self vod review? and does anyone have any tips on this topic?