I've often found myself looking at an aircraft approaching from my left (say at 10 or 11 oclock) and maybe heading towards me or across in front of me although not necessarily on a collision course - maybe at a different height.
The rules of the air say I should turn to my right but that assumes he will also move to his right. In my experience these aircraft zoom past and don't seem to have spotted you at all so what would others do in this situation?