Simple tip to sharpen images in realistic way.

Our final output would be like this

Open a Jpeg

Duplicate the layer by Ctrl+J

Desaturate the below layer using Ctrl+Shift+U or gradient map (Black at Position 0 and White at 100)

Goto filters - Other - HighPass (move the slider to get a median highlights and shawdows)

and its over now

simply change the Blending mode of the above Jpeg into "Overlay"

give's an astonishing output.