Black Tie indicates that a tuxedo is to be worn by guests.
The traditional black tie tuxedo has satin lapels and a satin stripe down the outside seam of each pant leg.
Your trousers will sit higher than regular suit pants, and a waistcoat can be worn to hide your waistband.
A black silk bow tie, white pocket square and pair of black patent Oxford shoes complete the look.

These days there are many variations on this theme.
In place of a tuxedo, a slim-fitting dark suit can be worn with a bow tie and pocket square.
The bow tie can be swapped for a black silk necktie.
Black shoes are a must.
Boots are really popular as they not only sit well under your trouser cuffs
but can be worn with your other suits, chinos and even jeans, making them a great investment.