Take the bottom right and left corners and make an accordion fold strips all the way up to the top right and left corners. If you press these with an iron the pleats will be nice and sharp. Leave unironed for a wavy casual look. (but ironed looks neater) You will now have a thin band the width of your accordion fold.
Fold the serviette in half so that is is now half it's length and slip a serviette ring over the fold end of the accordion strip and pull gently about 1 inch ( 2.5 cm) up.
Fan out the accordion pleats at the top to make a pleasing balance to the serviette. Present on a plate.