I'll be short.
I have identified that one of my main problems today is my memory, and so I'd like to work on it.
Searching for advice on the internet give way too many answers, and I really don't know which ones to trust.
Have you ever tried any exercices to improve your memory? Do you know any good blog posts about that topic?
Spaced repetition is proven to work.
Many of the supermemo articles are good -
(I don't know if all of them are, it's been a while. As always, be critical/skeptical, but some work)
A couple other points:
IMMEDIATELY try to implement something if it's interesting to you, and the chance that you do so goes up by a lot.
Re-read great books multiple times over a few months. It's what I do, especially with actionable content dense books like Getting Things Done, The Ultimate Sales Machine, Never Eat Alone, etc. Ray Dalio's "Principles" is one I re-read front to back multiple times, it's an amazing read.
Also, you could just rely on tracking/systems and forget stuff. I've given up trying to remember a lot of things, and instead rely on my calendar/to-do list, and just forget things until it's time to work on them again. It's scary, but it mostly works. Remember to back up anything mission critical like that!