The cover should never be empty, or what is called a naked cover . Either a show plate, folded napkin, menu or preset first course should be placed between the flatware. The napkin fold and placement of the napkin on the table can add interest. The napkin can be placed in the center of the cover, to the left of the forks, or fan folded and placed in stemmed glassware. An interesting twist would to have each napkin a different color, or with a different fold.
Planners usually consider color more than the napkin fold.
The type of fold is determined by the formality of the event and the location of the napkin on the table. A flat fold would be preferable if a standing menu or a name card is used. Flat folds are usually a better choice for outdoor events, which could be windy. A nice touch is to have the servers unfold the napkins for the guests and lay them across the lap. If a group is having several banquets, use a different fold for each meal.