ON CORRECT PHONE MANNER
Simply picking up your phone and saying "Hello" is the mark of a very basic individual. You must greet the caller properly ("The Bouquet residence, the lady of the house speaking") and factually ("I am a highly desirable private residence in an area of outstanding natural property values"). Oh, and if you can mention your "pearl-white slim-line telephone", all the better.
Modern society may take a regrettably lax view on pre-marital relations, but that doesn't mean you should. Do not kiss on a first, second, or ideally any "date", and be sure to avoid any glimpse of a bedroom until you are sufficiently betrothed. Just remember how Hyacinth reacted when she thought Emmett was Elizabeth's lover: "I warned her against watching Channel Four... I cannot have my next door neighbour turning her home in a house of ill repute, just think what it could do to the property values."
When it comes to dressing your abode, the provenance of the furniture is very important. "Flat-pack" things from some Swedish shop simply will NOT do for anybody of breeding. Instead, you will need furniture styled after those found in royal households - like Hyacinth's three-piece suite which is "an exact replica of one at Sandringham House." Be sure to have it delivered in a van which has the royal warrant displayed on its side, for the benefit of your neighbours.
ON CORRECT DOOR USAGE
Hyacinth says it best: "I think it's so common using back doors. The proper way for my guests, I always feel, is through the front door."
It is an unfortunate biological fact that humans have pores through which "sweat" can travel, leaving unsightly marks on clothing and a most unbecoming sheen to the skin. One should avoid sweating in front of others at all times. As Hyacinth tells Richard while he toils in the sun: "If you have to perspire, I wish you'd go into the back garden so you won't disturb people who respect us socially." Quite right too.
Breathing is very nearly as bad as sweating. Once again, Hyacinth puts it best: "I don't think it's quite nice to hear people breathing." The sad fact is that "evolution hasn't replaced our bodily functions with something more tasteful", so in the meantime we have to try to breathe as tactfully and discreetly as possible. (It's worth noting that when Richard pointed out they were "merely mammals", Hyacinth was having none of it: "What a thing to say to somebody with a solid silver self-cleaning sauce separator.")
ON MEDICAL CONDITIONS
If you insist on suffering a medical ailment, be sure to make it a respectable one. If it isn't, you'll just have to pretend for the sake of maintaining your social standing. For example, if - like Richard - you were to have athlete's foot, DO NOT inspect it ("It's very inner city to stare at your feet"), and most certainly do not tell people it's athlete's foot. Gout is a more socially acceptable story, for it is "painful but polite".
ON THE MAIL
It is a breach of the most basic etiquette to allow your letterbox to be violated by letters sent with second-class stamps. Have a word with your postman, and if they seem baffled then remember the exact wording used by Hyacinth: "I object to having second-class stamps thrust through my letterbox. I should have thought postmen would be trained to recognise first-class stamp houses." That should do the trick.
Finally, remember it is very rude to succumb to snobbery. The last word goes to Hyacinth: "If there's one thing I can't stand, it's snobbery and one-upmanship. People trying to pretend they're superior. Makes it so much harder for those of us who really are."