We've all handed our camera over to a stranger for them to take our picture, only to be severely disappointed by the result. But fortunately, Redditor EMDX (or Marc Dufour to his friends) has a solution.
He recommends that, before you hand your camera to a stranger, you set your camera to spot-focus. Then, put the spot where you want your face to appear in the final shot — use the rule of thirds, perhaps — then simply tell the person taking your picture to, "put the dot on my face." Simple!
Marc Dufour shows us how the technique works in the image below. It's simple, but really quite effective—and probably the best you'll manage unless you luck out and happen to choose a pro photographer out of the crowd. [Reddit via Peta Pixel]