I'm not sure how much others can relate, but I am hopeless at remembering most of what I read or watch. Even when I spend several days pondering the same book chapter / paper / recipe / etc, taking thorough notes, there is no guarantee I will remember it six months or even one month from now.
I started to realize that I was collecting new data points about a topic but rarely making connections between what I already know and what I read. So, I've been trying to slowly improve my retention by being more purposeful about what I read and how I take notes. Some guidelines that have helped in the past two or so years I've been trying to become a better reader:
* Before reading, I try to make a mental note of what I hope to learn from reading, in as much detail as possible.
* While reading, I underline key words and take brief notes in the margin so it's easy to look back later and get a rough idea of what each section of the book or articles is about. I will write "?" where I am confused or where I disagree, "@" for interesting citations I might want to follow up on later, etc.
* After reading, I take very rough notes about what I thought the most important points were, my reactions, and what I want to know more about. Since I take Markdown notes, I can use #tags and [[bidirectional links]] to help myself find these notes later if I am ever reading about the same topic again.
* Some topics are important enough to spend more time on. I basically have my own "encyclopedia" of Markdown files for certain topics that I can add to every time I come across an interesting bit of information. This has been especially helpful for keeping track of random tidbits of information I learn about cooking.