What: Choosing one sensory detail that reveals a character or state instead of piling up description.
Why: The mind trusts a specific detail and fills in the rest; a list bores, a single detail engraves.
How: Ask: what is the one thing that, if the reader saw it, they would know everything? Cut the rest.
Common mistake: Describing five things instead of one telling one, so the impact drowns in clutter.
Exercise: Describe a grieving person with one detail that never mentions grief (a hand toying with a wedding ring).