how do you take & organize reading notes?

I’d appreciate your dropping comments if you have thoughts, suggestions or links relevant to good strategies for taking and organizing your “literature” notes.  I’m working with my advisees on this, and I have to say that my own procedures have been ad hoc and often unsatisfactory.  I have the index card  files from my notes taken in the 1970s that are useless now.   I (as many) have tended to do ad hoc literature reviews for particular papers, but find that I have failed to keep or organize good notes that I can return to for a subsequent project, so I either rely on the lit review from the past proposal/paper I wrote, or have to start over.  I often will remember something I’ve read but not be able to remember the citation or enough information to find it again.  I have zillions of poorly-organized photocopies made in the 1980s and zillions of poorly-organized PDFs saved since the mid-1990s.  So I thought I’d put this out to the scatterbrains to see if you have good suggestions, ideas.  We’re talking meta-suggestions for how to think about the problem, as well as tools or techniques.  It’s how to get the work done now for this project plus how to be able to access the work again three years or ten years from now.