If you are using a different yarn than the one I have used make sure to check your gauge before you start. Herringbone stitch knits quite a bit more dense than other stitches to you will need bigger needled and a higher stitch count.
Double Herringbone Stitch~ The double herringbone stitch creates a band of interwoven herringbone stitches. Now, this is an easy stitch for creating a decorative band of embroidery, but it’s not quite as straightforward as it seems, s
This Herringbone pattern is beautiful, and she gives lovely step by step instructions, WITH pictures! Whit's Knits: Big Herringbone Cowl - The Purl Bee - Knitting Crochet Sewing Embroidery Crafts Patterns and Ideas!