The Young and the Best Dressed : Fashion: Coming of age may be the subject of the glut of twentysomething shows. But as “90210” proved, many viewers tune in to figure out how to dress for the <i> Angst</i> -ridden occasion.

Scene I: A clutch of beautiful yuppies ponder their careers in a glossy Georgetown bar called “The Round Table,” namesake of NBC’s entry in the twentysomething TV sweepstakes. Enter Jennifer Clemente, a knockout D. C. attorney. She zeros in on the group, spreads her arms and swings her aerobically toned hips to show off her new power tool. A beeper.

Jennifer: Tah-Dah!

Jennifer’s reporter gal-pal: New outfit or what?

Jennifer: C’mon, you guys. This is not a fashion show.

Cut.

Not a fashion show? Jennifer, you’re a walking advertisement for Ann Taylor: white ribbed top, high-waisted, full-legged black trousers and a hip-length buffalo-check blazer with gold buttons.

And this is just the first episode.

Twentysomethings--and their coming-of-age Angst-- make up one of television’s hottest trends this fall, but producers are hoping to hook viewers with more than story lines.

Indeed, a new batch of casts promises to be as stylishly clad as their counterparts on “Melrose Place” and the show that ignited the youthquake, “Beverly Hills, 90210.” Among the new offerings are “The Round Table” (which could very easily be called “90210 Goes to Washington”); “Class of ‘96” (“90210 Goes to College”); and “The Heights” (“90210 Goes to the Guitar Institute of Technology”).

Other new programs, such as “The Hat Squad,” “Up All Night” and “Flying Blind,” are filled with enough fashion flash to send young viewers into shopping overdrive--assuming, of course, the shows are not canceled after a few episodes.

(Last week, “90210” placed 46th out of 89 shows in the Nielsen ratings. “The Round Table” was 68, “Melrose Place” was 74 and “The Heights” came in at 86. “Blossom,” at 21, outdistanced them all. “The Hat Squad” was 43; “Out All Night,” 64; and “Flying Blind” was 69.)

Even “Blossom,” a perky, 16-year-old character in a sitcom with the same name, has updated her look. Gone are the Doc Martens. Blossom is stepping out in platforms and white bucks. Her shapeless dresses are being replaced with tailored skirts and vests. Her look is more sophisticated . . . more, well, “90201 Graduates.”

As the ensembles roll into your living room, so will a closetful of styles. The designer mix is eclectic: Armani, Stussy, Hugo Boss, Diesel, Anne Klein, Gap, Big Star, Drizzle, Cross Colours, J. Crew, Men Go-Silk and thrift-store chic. Here’s a sneak at what you’ll be seeing.

* Vintage clothes--some with moth-eaten holes. Costume designers say “vintage” can be anything from a 1930s gabardine shirt to ‘70s bell bottoms.

* Working-class threads for men, such as long-sleeve thermal shirts worn under flannel or gas-station-attendant shirts and construction boots.

* Big belts teamed with short skirts for women, as well as business suits worn with lace-trimmed camisoles.

* Leather motorcycle jackets (Harley Davidson preferred) paired with faded jeans (instead of ripped ones) for men and women.

* Plaid everything, including sleeveless shirts with and without hoods, vests, baseball caps worn backward, socks, boxer shorts and four-inch-wide ties, and shadow-plaid two- and three-button sport coats. For men and women.

* Fedoras, oversized berets and cowboy hats for men. Velveteen hats with giant flowers for women.

Even the preppy look is making a comeback (“Class of ‘96”), with oversized V-neck sweaters worn over white T-shirts, khaki trousers rolled up to the ankles and chunky brogues.

“Viewers pay attention to the clothes, especially if they identify with a certain character,” says Jori Woodman, costume designer for “The Round Table.” The show is full of law-enforcement agents and lawyers who wear Italian suits in the courtroom, ripped sweat pants and T-shirts at home, and Levi’s 501 jeans and leather jackets on the street.

Roxann Biggs, who plays attorney Jennifer Clemente on the show, says her character is so obsessed with power suits that she buys them at $400 a pop--with a credit card. A future episode will focus on Jennifer’s unpaid bills.

Says Biggs, “I think if viewers identify with a character, they also will be identifying with that character’s style, because the two are almost inseparable.”

Says Vivica A. Fox, who plays a fashion designer on the NBC show “Out All Night”: “Television has the power to set trends.” And sometimes, to promote existing trends. Fox’s character will adopt the currently trendy menswear look, wearing vested suits, wingtips, ties, big shirts and hats.

The last time a television show influenced fashion in a major way, men across the country were wearing T-shirts under sport coats and stubble on their cheeks.

“ ‘Miami Vice’ is probably the best example of television’s fashion influence on viewers,” says Debra Berman, costume designer for “Class of ‘96,” a show about freshmen at a Northeastern college that will debut on Fox in October. She hopes the look of her show--working class and preppy for guys, skintight for women--will be equally as inspirational.

Berman’s real challenge is outfitting a character named Patty Horvath (played by Megan Ward). “The producers told me that she is only allowed to wear black because she’s from New York’s East Village. So I’ve added fringe to the bottoms of jeans and put tons of beads on her to add some variety. It drives the sound guy crazy.”

Martha Snetsinger, costume designer for the CBS show “The Hat Squad,” hopes the fedoras worn by the main characters will set off a trend that the movie “Dick Tracy” failed to ignite two years ago.

“Hats bring back the images of the ‘30s and ‘40s, the best style elements of an era when men were men,” says Snetsinger.

Members of “The Hat Squad” (who are police detectives and foster brothers) also wear suspenders with belts, long ties, colorful T-shirts under dark suits, cashmere jackets, silk shirts, jeans and trench coats.

Over on the set of Fox’s “The Heights”--a drama about working-class hipsters in a band called The Heights--costume designer Tish Monahan is pushing a blue-collar look “because we are trying to reach out to the youth who watch TV.”

“We are trying to be as real as real gets,” she says about the mix of jeans and thrift-store jackets worn by the cast.

“Because the recession is present everywhere we are trying to give the clothes a gritty look,” Monahan says. “The characters are a little less than middle class. They’re on their own. So the look is very vintage, which is very hip.”

Monahan says her “real-life” approach to the cast’s wardrobe means “keeping in mind that in real life these characters probably only have seven or eight shirts, a couple of jackets--one probably very well-worn leather--three pairs of jeans, old vests and Doc (Martens) on the feet.”

“Fifty percent of my shopping is out of second-hand stores, and the rest of it--washed out and faded--is made to look as if it comes from second-hand stores. That’s the look today,” she says, and then pauses.

“The look these days is not a return to ‘Dynasty.’ ”