What are the 10 critical mistakes almost all job-seekers make?

Richard Lathrop, author of Who's Hiring Who and director of The National Center for Job-Market Studies, has compiled this list of common errors:

* Assuming that no suitable job opening exists. To believe this, says Lathrop, is to "tremendously handicap" any job hunt. His research suggests there are millions of good job openings every year, though it takes a certain amount of initiative to find many of them.

* Failing to assess properly what you want to do. "A guy may be awfully good at landscaping work, but he hears of a job as a crewman aboard a shrimp boat," and takes it. The months and years mount up and even though he hates the work, he sticks with it. Such people "let fate trap them." Find out what you like to do and what you are good at, and then don't settle for a job that doesn't meet that criteria.

* Poor presentation of qualifications. The average resume' simply lists an applicant's work experience, which an employer often finds difficult to assess. To stand out from the pack, Lathrop recommends preparing a resume' or brief letter stating specific accomplishments and abilities to offer the firm.

* Too heavy reliance on want-ads and employment agencies. Use them, he says, but remember that 75 percent of job openings may never be listed.

* Not knowing which employers offer the best prospects, or how to contact them. "Small organizations are far more receptive and offer most of the available opportunities. Big organizations are much more difficult to deal with. They've brought saying 'no' to an art." A suggested opening gambit: "What I would like to do is persuade you that the next time a suitable opening occurs, I'm the person you ought to hire."

* Failing to pursue the maximum number of interviews. When writing an employer, conclude with a sentence that you will be phoning in a few days--and then do so. "Taking the initiative and following up multiplies interviews many times."

* Not researching a firm in advance. "Disastrous from two points of view." An informed applicant "learns if he or she wants to work for that outfit"; "job-seekers who are familiar with an employer's problems, who can talk knowledgeably about the operation and who have ideas are way, way ahead."

* Not controlling the interview. Many employers are "amateurs" at interviewing, so a savvy applicant develops techniques to put a potential boss at ease. The applicant also should bring the interview back on the topic if the employer starts to ramble. The time you have to sell yourself may be limited.

* Failing to negotiate for the best-possible pay. Don't talk money until the employer "is so excited about the prospect of hiring you" that he or she "is willing to do a great deal to bring you on board." Most jobs have a salary range; the trick is to learn the range in advance and ask for 10 percent over the top.

* Being unaware of how the job market works. "Go to the library or the bookstore," says Lathrop, and take out several recommended books, study them, pick one that makes the most sense to you and do exactly what it tells you to do."

Lathrop's "essential message": It's not necessarily the candidate with the best qualifications who gets the job; it's more often the one who is best-prepared for the job hunt.

Lathrop will lead an all-day seminar, "Winning a Good Job in a Hostile Market," on Saturday, Oct. 23, from 9 a.m. to 4 p.m. at the River Road Unitarian Church in West Bethesda. The fee is $35, with the proceeds going to the church's community activities. For more information: 229-0400.

OVER 55s: A free job-search club for over-55s, for both part-time and full-time work, has been formed in Northern Virginia for residents of Fairfax and Loudoun counties, Fairfax City and Falls Church.

The Older Worker Employment Program, averaging 15 to 20 members, meets Thursdays at 2 p.m. at the Willston School, 6131 Willston Drive, Falls Church. Participants--including retired people--learn job-hunting strategies and exchange experiences. The oldest job-seeker to date: a 71-year-old accountant.

Sponsor is the Northern Virginia Manpower Consortium and the Area Agency on Aging. For more information: 790-1424.

FEDERAL JOBS: Deep in the Pentagon in a Navy Department office, Dortha L. Edwards has established a one-person Job Information Service to match federal workers with government job openings.

An accounting assistant for the undersecretary of the Navy, she originated the service in 1977 and maintains it on her own time before work, at lunch and sometimes in the evenings and on weekends. "I am usually in the office around 5:30 a.m.," says Edwards, a 25-year veteran of the government, "and work on the service until I start work at 6 a.m."

In four loose-leaf binders, she keeps an up-to-date file of vacancy announcements from federal agencies. But over the years, she has generated such a network of contacts she says she frequently knows of openings before they are advertised.

The service is sponsored by the Northern Virginia chapter of Federally Employed Women, of which Edwards is an officer, and it has the blessing of her Navy bosses. It is open to males and females for a $5 annual fee.

For more information: The Job Information Service is located in room 5D840 of the Pentagon. Listings are available from 7 a.m. to 6 p.m.