White tie, often called full evening dress, is by far the most formal dress code. You should not wear an ordinary suit but a black tailcoat, waistcoat and a white bow tie not a tie. You should always wear a white shirt and black shoes with dark soles. You shouldn't wear a wristwatch at all, it can be considered rude if you do. If you want to wear a boutonniere you should make sure it is a real flower, never leather or a false flower.
Benedict Cumberbatch, Tom Ford and Bradley Cooper below are prime examples of how to dress for a white tie event.
Black tie is the next step down from white tie. It is still very formal but you should wear a dinner suit instead of tales. Braces would be a great addition as they add style. You could also wear a cummerbund or waistcoat. You can wear either a bow tie or a long tie but we suggest a bow tie as it creates a smoother look. Again you should wear a white shirt. The colour of your suit can vary as long as it is a relatively dark colour. You could also choose to be a bit more adventurous with a velvet suit jacket.
Ryan Gosling, Chris Pine and Daniel Craig below are great examples of what to wear to a black tie event.
Some great examples of what you could wear to a black tie optional event are Will Smith, Tom Hardy and Jeremy Renner below.