If a window is wide enough, hang one drop centrally over the top. If it is not, drop a plumb line to one side of the window, about 120mm (5in) less than the width of the wallpaper, so that the first drop of wallpaper overhangs the window frame. Paste and hang the paper so that it lies loosely over one edge of the window frame. Using the paperhanger's brush, gently brush the paper into the angle between the wall and the window frame to crease it. Carefully peel the paper back and then cut along the creased line and brush the wallpaper back into position. Alternatively, you can leave the creased paper in place and trim it using a craft knife, leaving the paper in place in the angle and running the knife along the crease. Use a seam roller to press it down, if necessary.