I'll post it in parts starting with tea party invitation wording because her guidelines are pretty long. Take some of this with a grain of salt (or sugar!), especially the "servants" and "Best Society's" parts!
Please note that this is what was considered proper and tea parties then-- today, afternoon teas do not have to follow strict guidelines.
“DO COME IN FOR A CUP OF TEA”
This is Best Society’s favorite form of invitation. It is used on nearly every occasion whether there is to be music or a distinguished visitor, or whether a hostess has merely an inclination to see her friends. She writes on her personal visiting card: “Do come in on Friday for a cup of tea and hear Ellwin play, or Farrish sing, or to meet Senator West, or Lady X.” Or even more informally: “I have not seen you for so long.”
Invitations to a tea of this description are never “general.” A hostess asks either none but close friends, or at most her “dining” list; sometimes this sort of a “tea” is so small that she sits behind her own tea-table—exactly as she does every afternoon.
But if the tea is of any size, from twenty upwards, the table is set in the dining-room and two intimate friends of the hostess “pour” tea at one end, and chocolate at the other. The ladies who “pour” are always especially invited beforehand and always wear afternoon dresses, with hats, of course, as distinguished from the street clothes of other guests. As soon as a hostess decides to give a tea, she selects two friends for this duty who are, in her opinion, decorative in appearance and also who (this is very important) can be counted on for gracious manners to everyone and under all circumstances.
It does not matter if a guest going into the dining-room for a cup of tea or chocolate does not know the deputy hostesses who are “pouring.” It is perfectly correct for a stranger to say “May I have a cup of tea?”
The one pouring should answer very responsively, “Certainly! How do you like it? Strong or weak?”
If the latter, she deluges it with hot water, and again watching for the guest’s negative or approval, adds cream or lemon or sugar. Or, preferring chocolate, the guest perhaps goes to the other end of the table and asks for a cup of chocolate. The table hostess at that end also says “Certainly,” and pours out chocolate. If she is surrounded with people, she smiles as she hands it out, and that is all. But if she is unoccupied and her momentary “guest by courtesy” is alone, it is merest good manners on her part to make a few pleasant remarks. Very likely when asked for chocolate she says: “How nice of you! I have been feeling very neglected at my end. Everyone seems to prefer tea.” Whereupon the guest ventures that people are afraid of chocolate because it is so fattening or so hot. After an observation or two about the weather, or the beauty of the china or how good the little cakes look, or the sandwiches taste, the guest finishes her chocolate.
If the table hostess is still unoccupied the guest smiles and slightly nods “Good-by,” but if the other’s attention has been called upon by someone else, she who has finished her chocolate, leaves unnoticed.
If another lady coming into the dining-room is an acquaintance of one of the table hostesses, the new visitor draws up a chair, if there is room, and drinks her tea or chocolate at the table. But as soon as she has finished, she should give her place up to a newer arrival. Or perhaps a friend appears, and the two take their tea together over in another part of the room, or at vacant places farther down the table. The tea-table is not set with places; but at a table where ladies are pouring, and especially at a tea that is informal, a number of chairs are usually ready to be drawn up for those who like to take their tea at the table.
In many cities, strangers who find themselves together in the house of a friend in common, always talk. In New York smart people always do at dinners or luncheons, but never at a general entertainment. Their cordiality to a stranger would depend largely upon the informal, or intimate, quality of the tea party; it would depend on who the stranger might be, and who the New Yorker. Mrs. Worldly would never dream of speaking to anyone—no matter whom—if it could be avoided. Mrs. Kindhart on the other hand, talks to everyone, everywhere and always. Mrs. Kindhart’s position is as good as Mrs. Worldly’s every bit, but perhaps she can be more relaxed; not being the conspicuous hostess that Mrs. Worldly is, she is not so besieged by position-makers and invitation-seekers. Perhaps Mrs. Worldly, finding that nearly every one who approaches her wants something, has come instinctively to avoid each new approach.