Is there a difference in the sanding process for lighter or darker stains?

If yes, what would the difference be.

Also, how would you sand a herringbone floor.

Thanks

The sanding process should be about the same for any stain colour; with the addition of "water-popping" the grain for darker ones.
Sanding herringbone successfully should not be attempted by anyone less than fully experienced in the sanding process. If you are unsure of the procedures to follow, hire someone who has a great deal of experience, and observe.