I never bothered to retain case laws, but I had a fairly bright classmate who used recipe cards. Thin little recipe cards with plenty of space to write on both sides and nice bright colours as well. She's a top litigator now.
Paper is great, but have you considered storing those digitally at all? Software such as OneNote, Evernote, Joplin and many others like it can be quite useful, as later on you can search them easily for keywords, areas of law, case names, etc, and you can even embed files, screenshots, copy-paste articles and notes relating to it, etc...
It's a bit embarrassing to ask this but how did you keep notes of judgments/precedents? 1 notebook for each branch of law or cards? I've a few dozen old single side printed business cards that I can use. Thank you.
Fill the title, citation, topic/field of law, and ratio.
Later CTRL+F or sort by field.