Just assign Hazel a place to monitor (like a few folders, or your cluttered desktop) and watch it work.
It works by following rules you make using its menu of options, which you can apply to specific folders where your files go, or are supposed to go. Essentially an organizational assistant for your Mac’s files and folders, Hazel makes everything from tagging and renaming to moving, uploading, and deleting as simple - or complex - as you want it. Hazel may be my favorite utilitarian application.