Binding is a way of neatening a raw edge using a separate length of fabric, usually in a contrasting colour.
Piping is a way to emphasize a seam or edge and can add strength to corners which might receive a lot of wear.
For both binding and piping strips of fabric cut on the bias are used as this makes them slightly stretchy.
These free illustrated instructions will teach you how to complete both tasks easily.

Cutting bias strips:

To cut bias strips fold the fabric diagonally so that a straight edge is parallel to the selvedge (the side of the fabric).

Press this fold and use this crease as a guide to mark parallel lines for bias strips.

To join bias strips place two lengths, right sides together, right angles to each other and stitch.

Open out, press seam open and trim off the overlapping edges.

Binding an edge:

Cut bias strips 3 times the finished width of the binding required.

Fold both raw edges to the centre on the wrong side down the length of the bias strips and press.

Open up one side of the binding. Place this side of the binding onto the right side of the fabric with raw edges matching and pin.

Stitch along the fold line of the binding.

Fold the binding over the raw edge to the wrong side of the fabric.

Pin and slipstitch fold of binding to line of stitches on the wrong side.

Piping:

Join bias strips to required length and wide enough to cover cord and leave ½" (13mm) seam allowance at the side.

Lay piping cord in the centre on wrong side of bias strip.

With raw edges matched, stitch along length of bias strip, close to piping cord using a zipper foot on your sewing machine.

To join piping, trim the cord ends so they butt together firmly and secure them with sewing thread.
Trim bias strip so that one end is ¾" (2 cms) longer than the other.
Turn under 3/8" (1 cm) to overlap raw edge and slipstitch.

To attach piping, pin to right side of fabric matching raw edges with cord facing inward.
Snip seam allowance to help ease around corners.

Stitch in place on top of existing line of stitches using the zipper foot of your sewing machine.