From the book Build a world of crumbling glory. Never describe a thing unblemished, except as struggle keeps it so. Never describe a man irredeemable, except as he refuses redemption. Never describe a thing irrecoverable, except as it is utterly destroyed as the characters watch. Name your NPCs, always, and speak in their moods and gestures and voices. Act them. Act when it is appropriate; press your advantage when you have it, and seize opportunities when the players give them. Do these things: separate, capture, corner. Push a confrontation, announce trouble offscreen, warn of trouble that comes. Hurt, steal, overcharge. Have consequences catch up with them, press a decision, offer opportunities with or without sacrifice. Don’t strike arbitrarily. Let your NPCs act in stages, let them develop their plans. Take your time. Escalate appropriately. Only lock the characters down if they give you a golden opportunity or allow your maneuvers to come together without interference.