"The talk show is the ultimate colloquium of today's video-oriented, high-tech world," claims superhost Phil Donahue. "It's town crier and it's lamplighter."

And being a guest on one of these attention-getting, modern-day soapboxes can spell instant fame. For example:

* Producers at the TV station next door to pediatrician Lendon Smith's office in Portland, Ore., invited him over the discuss the flu in 1952. The audience loved him, he became a regular and went on to write several best-selling books, produce his own medical shows and appear 60 times on the "Tonight" show.

* As humorist Erma Bombeck was laying bathroom carpeting she heard Arthur Godfrey reading bits of her book on his radio show. She wrote to thank him, was invited to be a guest and now has her own segment on "Good Morning America."

* Therapist Wayne Dyer quit his New York City private practice and teaching job in 1976, piled copies of his book, Your Erroneous Zones, in his car and spent two years traveling across America--often sleeping in the back seat--plugging his book on radio and TV shows. The book hit the best-seller list, he wrote three more and now has appeared on more than 4,000 talk shows.

"Talk shows are among the most influential forces in our culture today," declares Donahue's executive producer Richard Mincer. "Literally millions of people watch and listen to the more than 4,000 interview programs broadcast daily throughout the United States and Canada. In the next 12 months, a minimum of 1.7 million guest bookings will occur."

"Only a very small percentage of talk-show guests--around 10 percent--fits the category of celebrity," says Mincer's wife, Deanne, 39, a writer, actress and talk-show veteran. She met her husband, naturally enough, on a talk show. In 1972 her creation of a male pinup calendar won her a guest spot on "Donahue," where Mincer, 44, has been a producer since the show's inception in 1967. They were married six years ago.

"The biggest misconception people have about talk shows," says Deanne Mincer, "is that you need to be a special sort of person to get on. But most guests are people just like your neighbor, your friend, your relative--or you."

For those who dream of a seat beside Johnny or Jane or Merv, the Mincers have penned a primer, The Talk Show Book (Facts on File, 193 pages, $14.95), conceived by New York literary agent Bill Adler who handled boss Phil's best-selling biography. Geared to novice guests--but useful for those who've dabbled in talk biz--the book covers everything from tour-circuit nutrition (calcium supplements at bedtime, vitamins C and B complex in the morning and peanuts throughout the day) to Margaret Trudeau's grooming tips (wear a neat "professional looking" outfit in any solid color except white).

The first step in the talk-show game, stress the Mincers, is "getting noticed." This requires "research, a strategy and tactical planning." It also helps, they admit, to have chutzpah.

"The meek may inherit the Earth," they write, "but they don't get booked on talk shows."

The most common mistake beginners make, says Richard Mincer, "is starting too big." Before contacting the "Tonight" show--"the hardest to get on," he says--"look in your own back yard." Shows most likely to follow up on queries submitted by would-be guests are the ones off "the major talk-show circuit."

Washington-area residents may be at a handicap since their back yard "is an influential market that may be tough to crack," says Deanne Mincer. "But there are still community-oriented shows to try." Or look to neighboring yards, she suggests, like Baltimore and Richmond.

Although some prospective guests hire agents or publicists, the Mincers contend that "with proper information and effort you can manage your affairs without one." An agent who "possesses good contacts in the field and has a good reputation can save you untold hours and energy," says Richard Mincer, "but a bad agent can hurt you more than help you.

"Image consultants are very expensive--$75 an hour and up. Unless you're a political candidate or corporation president you probably don't need one. The average person can practice in front of family and friends."

To get booked on a show, "listen to and watch the shows in your local market," says Mincer. "Get a sense of the various types--talk-service, talk-variety, talk-news--to target the spot where you belong. Different strategies will work for different programs. But even the most ingenious strategy won't work if you apply it to the wrong show, or if your subject is a deadly bore."

In developing your idea, says Deanne Mincer, remember that "in general, most non-celebrity talk-show guests focus on one or more of these basic subjects: political or social-psychological issues, health, appearance, the arts and how to do things better."

When you're ready to approach a producer, "use contacts," she says, "if you have them. Do you have a neighbor who works at the station? It's worth speaking to her to see if you can use her name when you contact the show."

Whether the initial approach should be by phone or mail, "varies from show to show. The basic rule is that the smaller the program, the more likely you will reach the booking person by phone and the greater the possibility he or she will prefer phone inquiries."

Producers are likely to be "turned off," the Mincers warn, by callers who:

* Phone while the show is on the air or being taped.

* Declare it's an emergency.

* Say they're returning a call when they're not.

* Demand to know if their material has arrived.

* Say their call is "personal."

* Are rude to assistants who answer the phone.

* Telephone producers at home.

* Call collect.

* Refuse to leave a message.

* Keep them on the line after the idea has been rejected.

But even after you reach a producer by phone, you'll usually be asked to send "a well thought-out, persuasive, comprehensive package of materials."

Applicants reluctant to send all their material, "can begin with a basic letter that clearly outlines the thrust of your idea," says Richard Mincer. "Since it may be all they'll see, it better be good . . . neatly presented and well written. Include your address, phone number and a listing of additional items available."

To enhance your chances, "you can send a package containing every scrap of persuasive material you can send--as long as it takes not more than 15 minutes to read." Consider including: a cover letter, biographical sketch, photograph, clippings, other talk-show appearances, videotapes (find out what size the station uses) and the product--or a picture of it--if you have one.

Most shows will return valuable material such as videotape, "but be prepared to go without it for awhile." Few, however, will return books or re'sume's.

While gimmicks--such as T-shirts or cakes--"will usually get the attention of the production staff," says Mincer, "it is possible that your attention-getter will be seen as an annoying disturbance that could decrease rather than increase your chances."

If you're rejected, they write, try to find out why and learn from it. "Keep your confidence. Reconsider your approach. Would your appearance be enhanced by adding a demonstration, slides, audience or host participation, staging a debate, including other speakers on the same subject, creating a quiz?"

If you do get booked, "prepare yourself," Deanne Mincer emphasizes. Ask the production staff: how long your interview will last, if the host uses prepared questions, if the program is live or taped, if there is an audience, who the listeners are, if there will be phone calls, if they cover expenses, if there is a makeup person, if they prefer certain clothes colors.

Before showtime, she says, "make certain that a list of highlights has been provided to the interviewer. Many times they won't have time, or prefer not to read everything you've sent. Then rehearse your message and the key points you want to emphasize. Practice putting them in brief, clear sentences.

"One producer told us that if you can't capture the thrust of your issue in one sentence, he probably doesn't want you on his show."

When dressing for the show, she says, "be yourself. If you usually wear overalls and that's part of your message, wear them. If you're a business person, dress as you normally would for work."

On the air, says Richard Mincer, "if you're less than enthusiastic you're defeating your purpose." And never tell an interviewer that "the answer to the question is on page 99 of my book."

If a question catches you off guard, "remain calm and as polite as possible. Answer as many questions or accusations as possible, but remember that you have a right to refuse to answer truly unfair questions."

Should the interviewer become hostile, he says, "don't blurt out a protest that would weaken your position." Instead, he recommends the "bridging" technique. You "turn the issue around from a negative to a positive and guide the conversation away from a topic you don't want to discuss toward topics you do want to talk about."

All this advice, says Deanne Mincer, "held up pretty well" on their own recent tour to promote their book. Their biggest problems: "starting a story and wondering if we'd already told it to that particular host," and "boredom."

"We took our own advice and were careful not to overbook so we'd never be late or hassled," says Richard Mincer. "Fortunately, we brought along a deck of cards."