Bead Weaving Flat Herringbone
This form of the stitch is ribbon-like and can be as wide or narrow as you want. It is usual to work with an even number of beads because each angled pair makes a column. Once you have learned flat herringbone, other forms of the technique are easier to grasp. The wonderful Jill Wiseman has a very good video tutorial on the basics. If you want to try something more, how about this tutorial on braided herringbone.
Bead Weaving Tubular Herringbone
This form of the stitch is rope-like but hollow. Be careful not to make the circumference too big else the structure may flatten. I would suggest no more than 6 beads in a round. Use smaller seed beads with this technique to make great ropes for pendants. Use Superduo beads to make chunky chokers or bangles. This Artbeads Mini Tutorial with Leslie Rogalski has some good tips and instructions. Using Superduo beads is more challenging, but if you want a tutorial go here.
Bead Weaving Twisted or Spiral Herringbone
This form of the stitch is very like tubular herringbone, but with a twist. As such, the structure is less likely to flatten than tubular. Use different colours to enhance the twist, but still stick to 6 beads in a round. If you have gotten to this stage, consider yourself advanced in this technique. Kelly Dale from OffTheBeadedPath has a great tutorial using size 8/0 seed beads.