I would think that organization is a very personal thing, and that each person should come up with a method that works for them.
That said, I'll share my methods, since it was asked for. My vinyl is in genres, with preferred genres on the left and lesser ones as you move right (this is vinyl on a shelf). Within each genre I have preferred artists/bands on the left and lesser preferred further right. Within each band is chonological order of releases. CDs are by genre, with the first section of each genre being compilations in alpha order, followed by artists/bands in alpha order.
When I had cassettes, I had them organized by manufacture, then model line - in the order in which I bought them. Completely regardless of the music recorded on them, but it worked for me.
My dad has his vinyl in alpha order in a cabinet in the living room. On top of that was a flip tray from a record store with "current faves" in the order of last played in front. Lesser artists were in the basement in his office, in alpha order. Least popular were stored in the garage on huge shelves he built. No idea on the order there. Random perhaps.
I won't even begin to describe how I have the files on my hard discs organized.
Whatever works!