Books on men’s fashion are full of rules. It’s good to learn them and a sign of class to know when to break them and when it’s better to stick to them. Some rules have become obsolete and some should be remembered even though they may seem dated or passé.
Do take off your hat when you enter a private home or an office. Don’t take it off in public buildings or elevators. I personally also lift my hat when I greet a lady but I am aware of the fact that the majority of people considers this as a very strange habit.
Suits are meant as a combination of jacket, trousers and sometimes a waistcoat. Everyone will agree that a suit is not complete without the pants but nobody seems to think so when the jacket is removed. Don’t take the jacket off in public even if everybody else does. Style is very often a matter of discipline.
White shirt and black shoes are a must in the evening. The modern dresscode of ”come as you are’ suggests that it is okay to wear the light blue shirt and brown shoes from daytime business into the evening. If you don’t have a chance to change it is indeed okay but you will so much more elegant if you change into a white shirt.
Black tie calls for a black bow tie. I know that in the US many actors like to wear a long black tie with their dinner suit but tradition and proportion call for the bow tie. Dinner suits are cut with long lapels and low cut waistcoast to show off a maximum of white shirt front. Don’t block the view with a long tie.
Ties for business should look serious. Don’t wear funny or silly motives. This is well known and seems sensible. I don’t agree with fellow style critics that comdemn motif ties in general. Many tie makers offer very tasteful designs with motives. In many business situations plain ties are the better choice.
Finally it still applies that it is better to be overdressed than underdressed in business. The opposite applies to private occasions. Still I generally find it less embarassing to be overdressed than underdressed no matter what occasion we think of.