Hanging Wallpaper: Making Seams
Place the new strip as close as possible to an affixed strip. With your hands flat on the new strip , push it gently up or down to align the pattern, keeping fingertips away from the edge to avoid tearing.
Push the new strip toward the old one until the edges of both strips touch and just begin to buckle. Then go over the seam with a smoother. After 10 to 15 minutes' drying time, run a paper roller along the seam in short up-and-down strokes.
In some spots, strips cannot hang exactly parallel -- in a corner, for instance, where walls are uneven. Positioning one strip to overlap another by 1/16 inch lets you cheat the alignment. Because an overlap creates a ridge, avoid using this seam in a prominent place. For thicker, fabric-covered papers, run a single-edge blade through both layers of the overlap, and peel away the underlying layers.