Before you start, read the instructions that come with the wallpaper. After this, measure the width of your wallpaper. Deduct approximately 5 centimetres from this figure, then use the tape measure to mark this distance out from the corner of the wall. From this mark, use the spirit level and pencil to run a straight line from the top of the wall to the bottom. This line is where the edge of your wallpaper will be. You need to allow the wallpaper to overlap onto the wall next to it, so you can cut it cleanly in the corner, after hanging it.