Here’s how it all works.
I listen to the radio. Sources of proven reliability include Cerys Matthews, Mary Ann Hobbs, Shaun Keaveny, Iggy Pop (all on 6 Music), and Sounds of the 60s (radio 2). I hear something that makes me go ‘oooh’ or ‘wow’, catch artist and title on the DAB radio mini-display, make a note on the kitchen whiteboard, transfer the details to paper, and pin to computer room cork-board.
A key step is to leave things for a few weeks, by which time I’ve completely forgotten the sound, other than knowing it’s of interest. I locate the song on youtube, vimeo, or soundcloud and often have great fun (re-)discovering the song and its brilliance, such as this