The western bow tie, also called a string tie, was a popular style in the 1800s. Few men still wear this style today, but it is sometimes employed in western costumes or period outfits. You can buy these ties from some specialty clothiers, but it's easy to make your own out of a piece of satin ribbon. This way, you can also choose the color and ribbon width that appeals to you most.
Put on a collared shirt. Put the ribbon around your neck and under your collar, adjusting the ends so that they are the same length.
Hold each end in each hand. Think of the end in your right hand to be end A and the one in your right hand to be end B.
Lay A over B, and pull them snugly around the neck.
Tuck the end of A behind the overlapping layers and pull it up through the neck loop. Pull it all the way through.
Lay A over B again.
Pull the end of A around the back of B, creating a loop between the two layers.
Push the end of A through this loop, and pull it somewhat snugly. This will finish the basic bow shape.
Pull the two bow loops in opposite directions to snug the tie against your neck.
Smooth out and unwrinkle the center knot.
Adjust the two hanging ends until they're of equal length.
Trim both ends to the desired length. Traditionally, these ties extend about halfway down the length of the shirt, but you can hang the ends as short or as long as you like.
You can also find pre-tied versions of these ties at costume shops and some western outfitters.