Clearly mark the holes of fixing plugs for pictures and mirrors before wallpapering a room, particularly when using heavy wallpapers. This saves a great deal of time that would otherwise be wasted in finding their original position. Do this by wedging the ends of wooden toothpicks into the holes, leaving about 6mm of toothpick protruding. These will pierce the lengths of wallpaper as they are being hung. Remove them just before reinserting picture hooks or any other fixings that have been removed.