Dark clothing is usually worn. Gentlemen wear dark suits or jackets, a white shirt and a black tie, whilst close family members wear a white tie. The people mentioned by name in the death announcement are the ones who usually wear a white tie.
If nothing is mentioned in the death announcement then dark discreet clothing with white nearest the neck, dark socks/stockings, matt fabrics, long sleeves and low heels are appropriate.
If the dress code is stated as optional, then black, grey, dark blue or another discreet colour is suitable.
If light coloured clothing has been requested, it means that the family wish to avoid a dark impression. Most colours in this case are acceptable but you should avoid bright red or yellow and other very strong colours and stick to softer shades.
If you want to follow traditions, silver jewellery and pearls are suitable.
Hats with veils used to often be worn, something many women felt secure in, as they were able to conceal their faces and their grief.