It's a line from an old song by The Association (early 60's). But it applies to my photography too often to be ignored. My picture "Portrait of John Deere" is a good example. Just before I took this shot (not great, but interesting), I was in the ditch across the street, trying to get my definitive "healthy Indiana corn crop" shot. I had envisioned a tall stand of corn lit by the early morning sun, with nothing but blue sky behind it. I was using a real low angle - very dramatic!
I had my location all picked out, just off CR 30 and CR 9. The corn is at least 9 feet tall, and glows emerald green in the early sun. With luck and the right angle I'd have nothing but blue sky and clouds behind the towering corn.
I showed up but the sun didn't - Lost in early morning mist. Blue sky was missing too - too much haze - No shot! (Maybe another day...)
Fortunately, something told me to "Turn around, look at me..." It was the John Deere tractor parked in front of the barn right across the road. For some illogical reason, 'turning around' has often uncovered an unexpected photo opportunity that's every bit as good as the one I had come looking for.
You might want to try the same simple step - After you get the shot you came for (or not, like me), turn around and see if there isn't another shot worth squeezing the shutter for right behind you.
I'm the type of person that plans my photos - sometimes days in advance. But I have to admit that some of the best photos I find show up without planning. I use "Turn around, look at me..." to help me remember to keep my creative eye exploring.