Materials required to complete a decoupage project with napkins are a candle or a box made of wood or paper, decoupage finish, a few small paint brushes, scissors or an art knife and decorative napkins. Other mediums can be used as well, such as hollowed-out eggs or small metal buckets. Typically, these materials are available at arts and crafts stores.
You only use the top layer of the napkin to decoupage. Some craft stores sell just the top layer. The design on the napkin should be easy to cut out. Napkins with white backgrounds work well on white mediums such as eggs or white boxes, because any excess napkin left around the design after cutting it out won't be noticed.
The background color of the decoupage piece greatly affects the look of the finished product, given that the napkin is transparent. Brightly colored or white backgrounds look best because they accentuate the transparent design. If the current background color of the piece doesn't seem suitable, paint it the preferred color with acrylic paint and allow it to dry before applying the napkin.
Separate all of the layers of the napkin, keeping only the layer with the design on it. Carefully cut out the design with a sharp pair of scissors or art knife. Paint a layer of the decoupage finish onto the surface of the piece with a soft paintbrush. Gently press the cut-out design onto the surface before the decoupage finish dries. Allow the finish to dry and coat the piece with one more layer of decoupage finish to complete the project. You can apply the final layer before the first layer dries, although doing so increases the risk of tearing the napkin.