More and more diners-according to restaurateurs polled- are leaving just one tip to be divided among the wine steward, captain, and server. Still, some restaurantgoers prefer to tip the wine steward separately because of extra attention or a superb recommendation. In that case, five or ten dollars given directly to him or her should suffice. As always, the tip should factorin the price of wine or alcohol and exclude the tax. It is customary to leave ten percent for poor to fair service; fifteen percent for average service; eighteen to twenty percent for excellent service; and twenty to twenty-five percent if the whole experience-from the greeting by the captain to the filling of your water glass to the attentiveness of the server-was so exceptional that it really made your night.