Piece | The "reverse-collar" necklace

Wear your collar necklace the other way around - as Karl had the models doing at Chanel with their necklaces resembling 

headphones, or for a more simple take, this Alexis Bittar collar. According to The Cut:

"By flipping it around and showing a bit of skin at the neck, the piece keeps a clean line that elongates rather than stunts the neck visually." But take note, "It looks best with some clavicle so wear it with a loosely buttoned silk shirt to the office or paired with a strapless dress for a cocktail affair."

Last image from here