Organizising digital tunes? I have yearly then monthly folders with everything I buy there. Then I add them to Rekordbox and Traktor, where I have identical tracklists, current (everything new, usually about 100 tracks, in order from ambient to Zach techno), and two back catalogue playlists (old and really old) which are in no order at all. I do a monthly back up from the music laptop to two external hard drives, and after that I do a clean up of the current playlist, when I usually prune about 50 tunes I no longer play.
If I have a gig I make a new playlist for it from those three playlists, usually double the amount of tracks I have time to play. Exactly like I packed a record bag in the vinyl days. I play several hours most weeks at home, so when I’m making a mix that’s not “live in the livingroom” I go through my histories to see what worked together.
This has been my method for about 10 years now.