Brevity.

Let my readers note that there’s no great need of long speeches at critical moments. Brevity is the soul of command. I’d used fewer than a hundred words to rescue my plans from a direct assault by my uncle. Too much talking suggests desperation on the part of the leader. Speak shortly, decisively, and to the point—and couch your desires in such natural logic that no can raise objections. Then move on.

(Xenophon’s Cyrus the Great: The Arts of Leadership and War)