According to Osho, witnessing may begin with the urge to escape suffering—the first, effortful movement—but it cannot be attained by effort. Like sleep, every attempt to 'do' it only keeps you awake. From the failure of striving, a second process starts: relaxation, non-doing, simple awareness. When effort drops, witnessing happens by itself.
You can’t force witnessing; relax and just watch, and it arrives on its own.