Head high, shoulders back, tummy taut, Lisa Mayer, 18, is learning how to walk. She is doing this in a class called Walk I, and she is here feeling awkward in Tysons Corner Center because she wants her picture on the cover of Vogue and Cosmo and Seventeen, wants, more than anything else, to be a star.

Even as she wobbles four steps forward on cowgirl heels, trying to pad instead of klunk, Lisa Mayer's Revlon eyes blaze green ambition. She dreams of being a model, sees carpeted runways and hears motor-driven cameras in her sleep. When she was 14 she modeled for Montgomery Ward, but showing ready-to-wear gratis isn't doing Diors at $2,500 a day, and Lisa Mayer knows she's a long way from a prepaid suite at the Waldorf. For now she's but a lump of clay in Auntie Gladys' hands.

Auntie Gladys is Gladys B. Davis, doyenne of dreams, a 60ish woman with auburn hair and a lingering hint of the freckled beauty that made her quite a successful model about 35 years and 40 pounds ago. Her finishing school and modeling agency, Cappa Chell, is one of the oldest in the Washington area. Sign up with Auntie Gladys, it says on page 953 of the Northern Virginia Yellow Pages, and "All of the Secrets of Beauty, Grace and Elegance Can Be Yours Within a Few Exciting Weeks."

For 30 years, Davis has been showing her girls the mysteries of the dots in the pointillist portrait of glamor. The mincing step. The carefully arched thumb. The blush that highlights the cheekbone and straightens the nose. The way to choose a chair that doesn't clash with an outfit. The handshake: firm, elbow close to your side, and never more than three pumps.

The Formula has brought Davis her share of winners, and they're all in a scrapbook in Suite 101 at Tysons, across an expanse of tile and Muzak from Garfinckel's.

Davis and her teachers give Lisa Mayer an outside chance for a plastic-covered page of her own. Five feet nine, black silk hair, good bone structure. But if Mayer is going anywhere, the front tooth she broke falling off her Schwinn must be capped, and the chicken pox scar between her eyebrows must be sanded. And there are the 15 extra pounds.

A senior at Washington-Lee High School in Arlington, Mayer plans no college next year, no other career besides modeling. Her mother and father (he writes tariffs for moving companies) "are encouraging me to pursue modeling as far as possible." And Mayer, well, "It's all I can ever remember wanting."

Nowhere in the Cappa Chell contract is a guarantee of future fame. Washington, says top New York modeling agent Jerry Ford, ranks back behind St. Louis, Detroit, Chicago, Memphis and Baltimore as a town for successful models. Making it in Washington is hard enough. Making it in New York is about as easy as riding bareback on a bucking bull. Some can do it. Most land in a heap.

What Lisa Mayer's $400 fee will surely bring, Davis says in her kind, breathy voice, is Cappa Chell Confidence, "something a girl can use every day for the rest of her life." As Davis sees it, her business is a service, a message too. Her philosophy, in essence, is that Emily Post and Mary Kay deserve places next to Gloria Steinem on the Mount Rushmore of womanhood. A bubble bath can be as soothing as a martini after a hard day at the office, she says. And it doesn't bloat your face.

Understand, most of the students who spend two hours a week here in this hall of full-length mirrors aren't as forthright as Lisa Mayer. Ask the 10 girls in her class why they're here and they'll mumble something about self-improvement and possibly some part-time modeling on the side. Mayer is the only one to declare, loudly, "I want to model for Ford."

But single out a few, take them down the corridor for a Tab at Farrell's Ice Cream Parlour. And with the drumbeats and scripted commotion of little Tommy's birthday party in the background, they will drop their voices low and speak of Every Girl's Dream.

Not that they're deluded, really. For years people have been telling them they had nice legs or pretty eyes or beautiful skin. For years they have read about girls like Brooke and Cheryl and Christie, about the hard work, but also about the high life, the diamonds and furs and nights on the town.

Somewhere deep inside they started counting the odds and figured, well, they had to go for it. So it's a long shot. Maybe, probably, they'll be disappointed. But this New York state of mind is a type that can linger. Better to play it out now than to be left with dull aches in their psyches for the rest of their lives.

Take Cynthia Barnsley, 17, a contestant in last year's Miss Maryland-USA pageant. She is 5 feet 4 and drives an hour to Cappa Chell from Olney every Tuesday night. After she graduates from Sherwood High School this June, she plans to attend Washington Business School in Rockville. That, she says, "is something to fall back on . . . . I like attention. I like dancing. The stage and the lights, well, I'd like to be famous."

Or Angie and Cherie Maetzold, towering blond twins of 17. They wear the identical round frame glasses and the same kinds of shoes every day. W.T. Woodson High School juniors, they'd like to be the Doublemint twins someday.

Why not?

Before a girl takes one step onto Cappa Chell's baby blue carpet to confidence, she has to get past Tricia Erickson.

Ten years, two kids and a marriage ago, the Cappa Chell director of admissions was the Carol Sellars Girl, a big-eyed model in ads for a women's clothes boutique in Idaho Falls, Idaho. Her best face was "a hard, foxy, sultry look," she says, and you can believe it.

Today she is 29, the consummate businesswoman, in a gray pin-striped suit with severely padded shoulders and a frilly, high-necked blouse. She drives a low-slung silver Corvette and does a little free lance modeling and works as a stringer for WWAY Channel 3 News in Wilmington, N.C. She's been taking care of her face since she was 14.

Like the model and critic of models she is, Tricia Erickson speaks of herself, of her face in particular, as if it belongs to some third person. A model is a walking brochure, and her message is that particular assemblage of eyes and nose and mouth and cheekbones and everything else she was born with.

"If you could see me in jeans, without my makeup and my hair done," she says, "you wouldn't think I was anything. My nose is crooked to one side and my lips are crooked, so I have to paint them on straight. I have a canvas of a face. It has good bone structure, but it's colorless. You see my big brown eyes; well, they don't show up without makeup."

She is just this way with all the girls, and with the women and the few men that come to Cappa Chell. Honest. Brutally honest.

The Interview:

The 14-year-old is wearing Easter colors on this 30-degree winter day, pink band-legged pants and a pink, white and green blouse, dark hose and white high-heeled sandles. Her mother, dressed in a pink winter coat, does most of the talking in the light yellow room.

"We've been kind of talking," says mom, "about the fact that she would like to start a modeling career, and we didn't know if she had the capability or the qualifications or if there's anything there that could be nurtured or so forth."

"Well, what we can do," Tricia says, "is go over your modeling potential. Is it okay if we do that? I'll have to be kind of a mean lady."

"I guess," says the girl, the only words she speaks in a 20-minute interview. She is 5 feet 4, blond, athletic cute, a candidate for the petite teen category. She knots her fingers, squirms in her chair while Tricia trains her hard, foxy, sultry eyes.

She will have to lose two pounds.

Teeth reasonably straight, but there's a gap in her mouth, a permanent tooth knocked out that will show in pictures.

Her mom is squirming.

Daughter's hair is too short and too dry.

Her facial features are good. But:

"What I think might hold her back a little bit is her nose. And your nose isn't big, your nose is not big, okay? It just goes out from the side on a slight profile."

The ears are fine, though.

Tricia says she thinks the girl has a 70 percent chance to do some teen modeling, "definitely not in New York, but possibly in this area."

The teen professional category is suggested, for girls 12 to 15 years, 22 lessons, five months once a week. It will cost $400 for the five-month course, down payment $150, payments $62.50 a month. No service charge or interest, no hidden costs.

"Well," mom says, a wifely look in her eyes. "The main thing we have to do right now is convince Daddy."

Davis looks a little like Miss Ellie on "Dallas," though the clothes are strictly Bergdorf's and Bonwit's. Instinctively, you want to respect her, and asking her age seems gauche. She won't tell anyway and says she's been lying about it since she was 28.

She won't tell you how much she makes either. Right now, she has 250 students who pay between $400 and $700. She will say, however, that the tuitions from the thousands she has taught these past 30 years have made her quite comfortable. She has a condo on upper Massachusetts Avenue and a house in Bethesda, a penthouse in Fort Lauderdale, an apartment in St. Petersburg and some land in Arizona.

Regularly, Davis cruises on Greek lines to the Caribbean, wears diamonds, emeralds and sapphires and, being from the blue grass city of Barbourville, Ky., she never misses the three jewels in the Triple Crown. In her office, along with handmade dolls and Boehm sculpture, she has an autographed picture of jockey Ron Turcotte riding Secretariat to victory in the 99th Kentucky Derby.

A woman of details, she once complained to her jeweler that a pearl in a ring was set 1/8 of a millimeter off. She reads Dow Theory. She has never married--her girls are her children, her friends her family. On Sunday, she gave a wine and cheese party for the Nigerian doorman at her building to celebrate his graduation from American University and his new job as an accountant.

"You should be able to say that every day was a marvelous day," she says, "that I did this and this and wasn't it fun and tomorrow I'm going to improve. And in order for you to perform well, you have to know that you look pretty good and know how to act."

This is what she says she wants for her girls. If they make it in modeling, great. But she wants them to make it as women first.

And at Cappa Chell, there is much to learn: Nod only once when meeting someone. Wait for a gentleman companion to open the door. The flow of traffic around a buffet table is always clockwise. Pause a moment when entering a room. Putting your legs under a chair when you sit will give an impression of insecurity.

A center part will make a nose look bigger. Don't wear long earrings or turtlenecks if you have a short neck, don't wear V-neck dresses if you have a long neck. A square face demands a round hat.

Lisa Mayer is standing in the hallway outside Cappa Chell. Her hips are cocked and her eyes are big and she is pretty but maybe not beautiful and she is searching for the right way to say this.

"Well . . . I . . . Oh, this sounds so queer . . . I want to be the best, I really do. Maybe these classes will help, or maybe I'll be sorry I didn't just want to be an accountant or something. But I've got to try. I just have to."