When you make a movie, you’re doing 10,000 things at once: from planning to executing, hiring, auditioning, communicating, and handling various tasks on a daily basis. So it stands to reason that you’re not going to remember everything you do right or wrong. Sometimes, mistakes will be repeated, good deeds will go unnoticed, and you could say the wrong thing at the wrong time and experience the effect of those actions later.
Keeping a journal is something that I can’t recommend enough. It’s a compilation of life lessons by you; it’s book material; it’s a great source of reflection, a list of all the good and bad compressed into lessons that will educate you with every new project you work on and prepare you for the next. Every time I finish a phase, whether its pre-production, on-set, or in post, I write something in my journal. I write every single thing I did wrong and every single thing I did right. And every time I approach a new project, I look over my notes from previous films. That is one practice that I cannot recommend enough.