Men's clothes changed only slightly from the 1850s, but a few slight details can help distinguish styles of the 1860s from the previous decade.
The men in the image below display a number of common 1860s men's fashions. The wide, tubular trousers and long sack coat are seen on the man standing in the foreground. The wide trousers were popular throughout the decade, while the baggier jacket style remained popular only during the early years of the 1860s. The man in the rear wears the single-breasted vest with flat collar, and, although barely visible, a watch chain is tucked through the top button hole and hangs down the front of the vest. The watch, worn in the vest, was the only significant accessory for men.
The man in the image below wears the mid-60s style jacket, which is shorter and more close fitting in the sleeves. This man's jacket is a solid, dark color, but many of these jackets had a checked pattern. Also visible in this man's attire is the very narrow silk tie at the collar. This thin necktie replaced the wide, billowing tie of the 1850s.
The single-breasted vest with watch chain is clearly visible in this man's attire.