Guests will be delighted to find cut flowers tucked into their napkins. To keep the blooms from wilting during the cocktail hour, slip the stems into little vials of water (available at floral shops). To fold the napkin, lay it on a flat surface, and fold in half widthwise so the folded edge is near you. Fold the top layer back down halfway. Turn the napkin over, and fold the edges into the center. Finish by folding the napkin in half.