Backstitch is done from right to left. Bring the thread up on the line and insert needle a little to the right. Now bring needle up again an equal distance ahead. Insert again at beginning of the last stitch.
Backstitch, Single Threaded
Work a row of backstitch. With a contrasting colour thread in a blunt needle, lace in and out of the back-stitches. Don't pull the stitches too tight.
Backstitch, Double Threaded
Work a row as in backstitch with a single-thread. Complete stitch by lacing back in opposite direction.