BY TODAY'S standards of conversation, anyone can talk easily with a new acquaintance. You need only exchange first names before entering into a recital based on one of the standard polite topics, such as what went wrong with your marriage or how much you paid for your house.

These conventions make it dangerous to agree to listen to polite conversation, but that is another Miss Manners problem. The one on which Miss Manners wishes to dwell now is how the habit of self-gossip has extinguished the ability of its practitioners to hold conversation with their own relatives. It is the most socially glib people, she has noticed, who tend to find themselves tongue-tied when faced with holiday tables populated by people of their own blood or choosing.

The reason, of course, is that your family circle knows perfectly well what went wrong with your marriage and how much you paid for your house. What is worse, they have developed their own opinions on these subjects, and are prepared to dispute your premises and conclusions by bringing in irrelevant material, such as how you treated your spouse or what investment opportunities you missed.

Naturally, this kills that form of table talk; or, if it doesn't, it soon brings on the desire to kill the talkers. How, then, are you supposed to talk your way through an entire meal with a bunch of people who sit on the other side of the turkey, looking like you?

There are special rules applying to extended families for each of the usual levels of conversation, which are (going from bottom to top): exchanging information, exchanging opinions, recounting stories and playing with ideas.

1. You cannot exchange the sort of information that one does socially, such as where you went to school and which old movies you regard fondly. But the satisfaction of discovering common ground is nothing compared to the license one has only among family, for blatantly reeling off triumphs ("I got an A-minus in Man and His Environment," "We had the whole house recarpeted") and trials ("My liver is acting up again," "They're beginning to lay people off in my office") and for feeling entitled to warm expressions of congratulations or sympathy.

2. The unsolicited exchange of opinions ("Why do you always fall in love with the same type?" "That haircut makes your face look even wider") is disastrous under all circumstances, but it is more freely practiced, and with even worse results, among family members. However, with relatives, unlike friends, you can request professional advice ("Come look at my sink" " . . . at Anastasia's rash" " . . . at our tax returns"), on the presumption that all good family members put their expertise at the disposal of all others.

3. Long narrations are awful socially, as they generally hold the attention only of those whom they are about, who also happen to be the narrators. But in families you can reminisce more freely, on the grounds that the characters are all part of the heritage of the listeners.

4. Playing with general ideas, amusingly or philosophically, has always been Miss Manners' concept of real conversation. In family circles, you are likely to have to pick a topic to meet a wider range of ages and interests than at parties ("Are the schools any good?" will rivet any generation), but you need not be shy about ones involving great sentiment ("What do you think the real spirit of Christmas is?"). And you should know only too well which topics are safe and which had better be avoided.

Once you master these rules, you will understand the great value of family life. It's that added intimacy -- and the fact that you can pick up the bones. MISS MANNERS RESPONDS

Q. I work in an office with approximately 10 other ladies, and one of my coworkers is driving me up a wall. Every time I or anyone else wears something new, she notices. If I wear something I haven't worn in year, she doesn't say a word -- only if it's new. I swear, she must have a list of everything I own -- how else could she know?

And she's so sickeningly effervescent about her comments -- ''Isn't that a new blouse? It's wonderful! I love it, and you look terrific in it!'' If anyone loses one pound, ''Aren't you losing weight? My, you look simply terrific!''

Now, I'm not opposed to compliments, but she seem to overdo it. And the noticing makes me wonder what she's thinking when I gain a pound and am wearing something that is 10 years old and shabby.

Is it really polit to ask if something is new and if one is losing weight? Is there a polite way to let this lady know that it is none of her business how old my wardrobe is, and how much I weigh at any given time?

A. Congratulations, madam. You win Miss Manners' award of the day for helping to stamp out plesantries, and for making the well-intentioned see the errors of their ways.

Miss Manners will try to remember not to wish you a good morning, lest you assume that on other days she is hoping you will have bad mornings. She will refrain from saying ''How are you?'' because the physical welfare of your body at any given time is really none of her business.

Those who are silly enough to take conventional pleasantries literally, and surly enough to resent them, leave others, such as you coleague and Miss Manners, with nothing to say to them. So a good day to you, madam. (Oops.)