HAVING DEVOTED her life to extolling the virtues of modesty and quiet charm, Miss Manners feels bound to admit that these are not wildy successful qualities to exhibit in job interviewing. Few employers are seeking models of self-effacing gentility to reward with responsibility and money.

In Miss Manners' day, there was no conflict between being a ladylike or gentelmanlike, and seeming competent and efficient, because ladies and gentleman did not seek jobs. The respectable solution, for aristicrats short of cash, was marrying for money. But now honest labor is appallingly chic, and everyone needs a set of business manners, as well as social ones.

The best job applicant is one who is able to sing his or her own praises without embarrassment, confident enough to steer an interview away from inappropriate areas, and persistent.

When you would demour, socially, with "Oh, it was nothing, really," you would, in business say, "I was graduated with honors, had the best sales record in my last job and left because I felt the job wasn't really using my abilities."

When you would tell a prospective host, "I think your company would benefit from my contribution." To a dinner partner, you might say, "Why, yes, my husband is the one over there with the blond mustache, and we have four beautiful children from three marriages"; to a personnel person, you say, "Well, I really don't think my personal life will have any bearing on my work."

Crispiness replaces flirtatiousness, showing that you know that other person's business is not nosy but intelligent; and bragging is the mark of the able worker, not of the bore.

But there is one social skill that can serve as your strongest asset in a job interview. In private life, it makes people fall in love with you and seek you for purposes ranging from honored dinner guest to spouse; and in business, it helps more than any other single qualification, with the possible exception of being the owner's eldest child.

That is enthusiasm. A look of vitality and happiness, an interest in the world and an eagerness to participate in life, is what is called charm in social miliey; but in the working world it is called competence.

One may practice such a look. It is chiefly done with the eyes. If they can be made to shine radiantly, the rest of the face will automatically compose itself into the properly attractive expression. Or practice staring into the mirror as if you have fallen madly in love. Most people have little difficulty with this, when they have thought it over.

Such a look, accompanied by short to-the-point remarks about one's abilities, one's invaluable experience -- not only in previous jobs, but in volunteer work, education and hobbies -- and one's deep interest in the work being done by the company to which one is applying, convinces an employer that what you can do for him is more important than what he can do for you.

It should make the face look so intelligent that it should see the wearer with dignity through such shabby interviewing tricks as being deliberately kept waiting while the employer takes a personal telephone call, or being badgered to take a drink when one knows one shouldn't. It should make refusals to disclose one's present salary or discuss how long one might stay on the job seem businesslike, rather than weaselly.

It is also useful, because you needn't change it when going from office out to dinner. MISS MANNERS RESPONDS

Q. My fiance and I both come from large families and have many friends -- unlike most couples today, we are both fourth generation in the city where we were born, and have gone to school here and plan to bring up our childern here -- and so we have been in one continuous whirl of parties practically since the day we were engaged. We are also having a large wedding, and there will be several parties before it. Mind you, we are not complaining. It's hectic, but it's fun. We are both sociable types, and plan to do lots of entertaining when we are in our new home.

My question has to do with being toasted. Someone is always proposing a toast to us, or sometimes just to me. People seem to think that champagne is the only fit drink for us now -- and again mind you, I'm not complaining about that, either. But last night I got a little high, and started telling funny stories about my husband-to-be's sister when she was a little bully in second grade, and hilarious anecdoted about the time I almost ran off and got married to a boy who got arrested, soon afterwards, for stealing cars. That is, I thought these stories were funny. Nobody else did. There were a few forced laughs, and my fiance turned white.

In short, I think I had better stop drinking so much at the pre-wedding parties, or there won't be any wedding party. Yet I know there is nothing more gauche than refusing to drink a toast. What shall I do?

A. Fortunately for you, there is something more gauche than refusing to drink a toast, and that is drinking a toast to oneself. Since you are the object of all these liquid good wishes, all you have to do -- in fact, all you should do-- is sit there, hands in lap, and smile demurely while everyone else drinks to you. (You are supposed to be sufficiently drunk on happiness.) If you can manage a blush, that is nice, too. It is only after the toast is completed that you may join the guzzle.

Q. I would like some advice on how to politely inform one's guest or date that the evening is over and you would like to leave. In most cases, an evening that begins at 7 or 8 p.m. would do well to be over by 1 or 2 that same night. It seems that if the message to leave is subtle, it is ignored, and if it is too direct, it is taken as an insult.

A. Speeding the parting guest is a social grace that no one can afford not to master. It is a mistake to think that wishing to close the evening is an indication that it has not been a success up until that point. This may be true of romance, perhaps, but not of a social engagement.

You are right that it cannot be done subtly. Refusing to serve more drinks, for instance, is not only a niggardly way of hinting, but it takes a while before the guests realize what is happening.

Miss Manners has heard of such direct methods as the host's saying, "Well, I'm afraid I have to get up early so I think I'll go to bed now," or looking at his own clock and saying, "Why you naughty clock, you're chasing my guests away."

But the method she prefers is one that cannot be taken for insult, because it is traditional -- only the tradition is that the guest, rather than the host, performs it. There is no reason, however, that the host cannot. He merely stands up and says, "This has been a marvelous evening; we must do it again soon." The key part is the stance. Few guests can remain planted in their chairs while their host or hostess is a standing in front of them beaming with smiles.

Q. I recently made dinner for my family at my parent's home. As we were about to dig in, my mother pointed out that I set the table incorrectly. Sure enough, there were eight left-handed places set. I calmly reasoned that, as it was my dinner, and I was left-handed, the table was not incorrectly set, just inconveniently set for seven of the diners. Well, a fearful battle ensued, and I felt honor demanded I stalk off with my turkey and those of my sisters hungry enough to agree that the table looked lovely. As time rolled by, I began to question the wisdom of my action. Could my mother have been correct? If I had had the dinner at my house could this problem have been avoided? Surely any place setting, made in the privacy of my own home, would be correct? What is Miss Manners' opinion? A. Miss Manners is so taken with the mental picture of you stalking off that she can hardly tear herself away from it to sort out the claims in this interesting family feud.

Are you a guest, obligated to do things in the fashion of the hostess, or does your cooking dinner make you temporary hostess? Does being grownup enable you to go against your mother's way of doing things, in her own house? To what extent is it also, in that sense, still your house? Can a minority (in this case, the left-handed) upset tradition in order to reverse a form of discrimination?

These are all interesting questions, with at least two sides arguable to each. But Miss Manner is left with still another question: Why are you trying to annoy your mother?