Plastic or cotton: Cotton piping cord is best for interior furniture and soft furnishings. Plastic piping cord is for outdoor furniture, marine and auto upholstery.
Cutting piping fabric: Use scissors and a long ruler to cut long lenghts of fabric, perferrably on the bias (diagonal) of your fabric. For 3mm piping, cut the fabric 4.2cm wide. For 4mm piping, cut the fabric 4.5cm wide. For 6mm piping, cut the fabric 5.5cm wide. These width will give you 1.5cm "flange". The flange is sewn into your seam, or stapled onto your frame.
Sewing piping: Cut long strips of fabric and wrap it around the piping. Use a zipper or piping/welt foot on your sewing machine and sew close to the piping cord.
Stapling piping: Secure the piping in place with staples, keeping it straight and taut. Reinforce the piping with tack strip.