I started out by playing the parts of a song that I memorized, like the lead vocals or a lead instrument (melody). The earliest song that I remember playing was the theme song from the Munsters (That lead guitar was easy to pick up). From there, I progressively advanced into playing chords. I think that when it comes to playing ear, you just have to start somewhere, since there is no "established theory" to it. Others may disagree, but that's what worked for me.
yielded
