At File:Neckcloth.JPG - Wikipedia there is a “regency style neckcloth tied in a bow”.
How does one actually tie such a knot? I would imagine that the neckcloth is not shaped like a modern bow tie, so some additional steps would be needed to make such a depicted tie?
It looks exactly like a bow tie (the real kind that you actually tie, not a pretied imitation) except that the ends are longer. I suspect you could use the standard tying method and it would work just fine.
In a square knot. We Yanks threw out the Brits BEFORE the Regency and pretend its fashions never happened. 
A modern bow tie is shaped like it is so that, when tied, it will look as it does . But the shape is not necessary to the knot; you can tie a similar knot in any long strip of fabric. As far as I can tell from the picture, the knot in this tie is exactly the same as the knot conventionally used to tie a modern bow tie.
(ETA: looking at the post by UDS) Are you disagreeing with me, an American Patriot? Why, I’ll…
(also ETA, drunkenly): Didn’t I tell sassyfras that? That he/she could adopt whatever his knot was and adopt it as his own? I mean, it’s just a friggin’ knot!
You get your manservant to tie it for you.
And then you wave him away with irritation.
This item is probably 3 feet long, and wraps around the neck before being tied (start with the center in front of the collar, bring the ends around from behind, and tie in a bow. There are many instructional videos on bow ties on youtube.
