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How far is it between the top and bottom wires? How far is it around? If you are working with a paneled shade, simply take the measurement of each panel; if you are working with a circular shade, measure the circumference (3.14 x diameter). This is necessary to find out how long and wide your strips of fabric need to be and the amount that will cover your entire shade. This is where the shade becomes all your own. Use one style of material for a battered, distressed look or use all types of coordinating colors and patterns. Just make sure they're long enough!  Add one extra inch for the seam allowance. This is needed to wrap around the wire frame.  If your lamp is 20" (51 cm) around, make sure you have fabric that, in total, amounts to at least 22" (56 cm) wide. You need adequate overlap to keep the wire frame from showing. Of course, greater overlap than that is always safe, too. If each strip of fabric is 2" (5 cm) across, have at least 11 strips of fabric ready. This ensures that it stays neat, doesn't fray, and looks professional. The edges will only be seen from the inside of your lamp. If you're pressed for time or simply can't be bothered, a simple trim is fine. Using your 1/2 inch (1.25 cm) on either side, affix the strip to the top of the shade with a staple gun, hot glue gun, or needle and thread. Repeat for the bottom.  If you use a hot glue gun and glue the material to the wire, you will not be able to gather the fabric when it's finished. If you use a staple gun, it's a good idea to add decorative trim around the top and bottom to obscure those tiny metallic lines from view. You can gather the material together if you stapled or used a needle and thread. Adjust the material to achieve the look you want. Beads, tassles, or extra ribbon can be added onto the top and bottom of your shade to hide any less-than-perfect areas or simply to add more flair.

Summary:
Take the measurements of your frame. Cut strips of fabric. Hem, trim, or edge the fabric with ribbon. Attach the strips to the top and bottom of the lampshade. Adjust the strips and add trim (optional).