First the bad news. Many of the fall clothes coming up from the top New York fashion designers won't mix very well with what is already in women's closets.

Now the good news.The new clothes, when skillfully done, simply look great.

Today begins the second week of showings by 30 trend-setting New York designers. It follows, with a breather of only a week, the shows in Milan, London and Paris. And by now it is clear that most of the designers are thinking of styles very different from the ones that have been around for a while.

The fashions for fall are more crafte, more highly styled-with more "dressmaker detail" and more shape. No more super-simple, easy-cut layers of clothing. The best of the new clothes fit close to the body and are expertly tailored, with attention to fine details such as pleated or padded shoulders, fitted waitslines, embroidery, beading and other decorative trim.

The new clothes look expensive, and they are-with prices up about 25 per cent from a year ago. But most designers are convinced that the public will willingly pay more, as dressing up becomes the style of the season.

"It's a totally new direction," says Calvin Klein, whose label is among the most coveted in Washington. "Everything is very shaped from the cut of the clothes, because women are very body-conscious today and want to show this off," he says.

"It's a change in silhouette, a change to stronger colors, and a total change for evening that will bring women to wear tremendous amounts of metallics, beading . . . even beaded suede, beaded leather, beaded georgerre, and hand-painted water colors."

Klein is working day and night to have his show ready for Friday. It seema a far cry from his other business: selling jeans at the rate of $100 million (wholesale) a year, producing 100,00 pairs a week.

And Ralph Lauren, master of ultra-classic and ultra-expensive clothes, has gussied up his sportswear with lace-trimmed shirts, antique jewelry and sweaters beefed up at the shoulders with pads and tucking.

Even Perry Ellis-who coined the word and defined the concept of "slouchy," baggy clothes-is pleatin and poufing sleeves, nipping in the waist of his coats and jackets, and putting circle skirts on some designs.

Donna Karan of Anne Klein is emphasizing less change in the clothes than the accessories. Her shoes always have open toes, sometimes an open back and a ribbon wrap around the heel. She shows her designs with hose and gloves in stron colors, including a model in a black coat with purple gloves. Her hats have feathers, her belts have beading. Color-insist Karan and Louis del'Olio, her co-designer-makes every state,ent stronger, whether it is several shade of purple in the same costume, or a mix of olive, grape anf gray flannel in the same outfit.

"It has a lot to do with the successful business woman," insists Marjorie Schlesinge Deane, chariman of the baord of Tobe & Associates, a merchandising consultant firm to stores across the country. "Whe no longer needs to hide behind the costume of her male co-worker. And she wants to look a lot spiffer than her secretary, who probably looks pretty good," she says.

Deane also feels that the new dressiness provokes confidence. "We're in a period when we want to stimulate all five senses," says Deane. "Take furs. They feel so good, make you look so good. In spite of all the concern of the environmentalists, no one can stop the growth of the fur business, because of how women feel wearing them."

Amid the complexity of the fall fashions, it's obvious that some designers have a better sense of what works and what doesn't. And as in any season, there is some wretched excess. Some sleeves are so puffed and shoulders so padded that they look like costumes for "The Wiz." Others are so wrought that the mood is more tarty than tasteful.

If the daytime clothes are dressy, the evening clothes are dressier still. And the gap between day and night is, if anything, wider. Some of Ralph Lauren's evening jackets are solid glitter; Calvin Klein has a 14-karat gold jacket; and Donna Karan has beaded a little suede hacket to the tune of $12,000 retail.

Some elements of the current trend have been around for a while. Paris designer Karl Lagerfield led the way in his very shapely collection of six months ago, and continued it this year. And women had already started to team dressier fabrics like satin with their tweeds (Calvin Klein recommends this year that you put a taffeta blouse with your tweed jacket for day wear.) Even those not so adventurous were already decorating their tweed blazer lapels: frist with stickpins, then glitter pins, now funny ceramic conversation pins.

Bernie Ozer, head fashio-hunter for the Associated Merchandising Corp. stores (including Bloomingdale's and Woodward & Lothrop) believes the new designs will catch on. "Women like change. With all their bitching they still like a fresh look," he insists. Eight years ago, he says, women felt that suits were "a pain. But look how they are taking them now because they are new again."

Karan is convinced, from the retail success of slim skirts and suits, that the new styles are on target: "I know women want their hair coiffed, want to wear makeup, want to dress up again. I want to do it myself. I'm ready to give up my pony tail for a Veronica Lake hairdo."

But are women prepared to give up the classic comforts of a simple tweed jacket and pants or skirt for some thing a good bit dressier when the new styles go on sale in July?

Obviously, designers fully except that women will stick with their old favorites, adding only a new outfit or two to their full wardrobes.

But Calvin Klein, like most designers and buyers, is optimistic: "The only clothes women don't like are clothes that are boring, clothes they already own, or clothes frivolous and not woth the money." CAPTION: Pictures 1 and 2, Black wool coat by Donna Kartan and Lois del'Olio, left; Perry Ellis pins up a sleeve, right; photos by Margaret Thomas; Illustration, Calvin Klein fitted jacket, left, sketched by Zack Carr for The Washington Post; Picture 3, Ralph Lauren's wool cardigan over lace-trimmed bluse, by Margaret Thomas.