It is a bit complicated what you want, since decorating a wall to cover the wallpaper with which it is wallpaper, but without spoiling it is difficult. You can place an acid glass plate that lets you see the shapes of the paper but that qualifies the pattern and color. Put a colored glass plate, in a shade that matches the decoration of the room. Line a DM board with a paper that you like, put a nice molding and place it on that wall so that you just let the background paper look a little. You can always put framed sheets throughout the wall, in a composition that covers a lot of surface area, but this option is complicated because it reloads, the paper is still visible and is the main wall of the room.