To wear a tie clip, also known as a tie bar, clip both ends of the tie to the placket of a button-down shirt. The tie clip should go between the third and fourth buttons of a dress shirt.
The purpose of a tie clip is to hold the tie in place. Do not wear a tie bar that is wider than the tie. It should be about three-quarters the width of the tie. The tie bar should be perpendicular to the tie. Just before clipping on the tie bar, pull the tie upward slightly. This keeps the tie from feeling constricting. Tie bars do not need to be worn with waistcoats or cardigans.