Look for loose Black pieces that might serve as targets and you come to the knight at h5 and bishop at d6. Ask if the lines to those pieces intersect anyplace the White queen can reach and you are led to Qd1. Or now think about this position from a defensive standpoint. Black just made the move Bd6, a mistake that turned out to lose him the game in the way just described. How would you avoid making such a move? By asking the same question about your own pieces that you ask about your opponent’s: which of them are loose, or will be after the move you are considering. And then you treat every loose piece as a vulnerability. In this position Black’s loose knight at h5 already was unfortunate and was a reason to pause before also moving the bishop to an unprotected square.