One must know the rules first, even if you are going to break them. Your pocket square should never match your tie. Ever. It should contrast and complement in colour, pattern and texture. Only wear one tie accessory. Do not wear a collar bar and tie pin. And avoid wearing a tie bar with your waistcoat; it is superfluous, rather like wearing ‘belt and braces’. However, you can still wear cufflinks with your shirt; they should be in the same metal but need not match perfectly. The breast pocket on your suit jacket should always hold a pocket square, with hand-rolled edges and of a decent size so that it overflows from your chest. Always wear a pocket square, even when you do not wear a tie.