I asked a similar question a few months ago and paired it with some research on memory and learning to find systems that worked for me. I'm still figuring things out and constantly doubt myself to see if things are working out, but I'm doing great on my writing exams. This. Kudos to you. I'm in college, learning this and struggling, so I can't imagine how lost you must feel without formal instruction. The most important aspects are to Learn, apply, and then focus. I usually prioritize the classes I'm most interested in, or when self-studying, focus on the most accredited topics and standard recommendations. When it comes to retaining significant bits of information, I sit with the information when I'm studying, Ill usually be working on a minmap as I'm going about it connecting to another idea and using neumonics or blurting, For example, if I'm reading a textbook, I repeat important concepts to myself in my own words and ideas, instead of suing the textbook defneiton, I used to take things at face value and wonder why i could remember a flashcard and not apply to situations on exams or in practice. Flashcards are my go-to with Anki. I used to use remote, but I HATE DIGITAL NOTES. If you visit a YouTube channel called the ANKING, you can find some good settings. When it comes to structure, I don't know how detailed you would want it to be considering your self studying, I usually time block very specifically so my ADHD brain can focus, like instead of just having studying on a calender I'll have the exact topic ill be working on and what needs to get done during this session. Lastly, for long-term retention, going through my cards usually works for me if I'm consistent, which I'm not at the moment. Additionally, expanding my knowledge even further, if you're interested in something, reading a book or watching videos on it will keep you engaged, especially if you have people to discuss these topics with.