Janet Coffin of Seabrook, Md., who has a master's degree and 11 years of experience in teaching, has been trying for 18 months to get a career government job in her field (personnel work or social sciences). In one energetic month alone, she says, she sent out 50 or 60 applications to various federal agencies.

There was a time, as recently as 15 years ago, when federal officials had to coax people to take the Civil Service examination, had to "beat the bushes" as one official put it for people who would accept "government work."

These days, as Coffin's efforts indicate, the search for a government berth is often complicated, frustrating and sometimes cut-throat. Last year, the Civil Service Commission reports, only one of every 11 of its career job applicants actually get a job.

Looking for an edge, Coffin and other job prospectors in this bureaucratic Sierra Madre are turning more and more to the services of a new breed of entrepreneur.These services ferret out an dsell information on federal jon vacancies and complex hiring terminology and procedures, which may vary from one agency to the next.

"At least they help you figure out where to send your applications, where you might have a chance," said Coffin, who is working as an analyst in a temporary public works program while she job hunts. Her husband, John, also found the job information useful recently when he made a change from one government job to another.

For the first-timers lie Janet Coffin, or for those with government career status like her husband, just finding appropriate job vacancies can be, as one expert put it, "an exercise in frustration."

There are over 200 separate federal hiring centers to keep up with in the Washington area alone, according to Judy German, founder of a bi-weekly newsletter called the Federal Research Service Report, based in Vienna, Va.

A personnel specialist, German launched the newsletter three years ago with 22 subscribers. That first issue listed 100 job openings. "We had made an all-out effort (to find vacancies) and I thought that was a thorough list.Now I realize it was dreadful," she said.

Her recent newsletters contain about 1,500 vacancies nationwide and overseas. The circulation has grown to 4,000 (at $18 for six issues) including libraries, congressional offices and one aircraft carrier at sea, she said. (The newsletter does not list "restricted" vacancies open only to those already employed at a given agency.)

German and her small staff collect the information from various agency personnel offices through phone contacts and leg work, she said.

Constant updating is important, she added, because the average "closing date" (after which no more applications are accepted) is only about two weeks after a vacancy is announced.

Based on their continuing dealings with federal agencies and on feedback from job hunters, German and others in the field offer tips on who is hiring, who's not.

HEW looks bad for management jobs right now, but Interior is hiring environmental experts, they note. The new Department of Energy will mean new jobs - but only if you have the right skills, and are already making the right personal contacts. And despite a glut of teachers in the continental U.S., the Bureau of Indian Affairs in Alaska has had a shortage of teachers all year.

A serious federal job seeker needs not only energy, but a clever strategy, according to Jim Hawkins. Last November, after 20 years as a civil servant, Hawkins started publishing a newsletter called the Federal Job Letter out of his home in Reston. A follow-up to a modest guide to federal employment called "The Uncle Sam Connection," which Hawkins wrote, the newsletter has 1,000 subscribers, he said!

"About 90 per cent of the government job openings around here are filled through personal contacts . . . People who just get on the Civil Service register and wait will die of old age before they get jobs," he said. He suggested various routes by which "an outgoing person" might wangle a personal introduction to the person actually doing the hiring.

A major frustration for many of those seeking government jobs for the first time, he said, "is that they don't understand that, when jobs are advertised, many have candidates that are preselected. I'd say about 35 per cent. It's not cricket. In fact it's often illegal. That's why they don't tell you, but it happens all the time."

The trick, he said, is to be the person who is preselected.

According to Judy German, "One of the biggest things the public doesn't understand is the extra consideration given to people who already work or have worked for the government. The agency has to have an effective merit promotion system for the present employees, to give them a crack at the job . . . But the public often feels this is inbreeding, unfair."

German also emphasized the importance of the formidable federal form 171, the basic job application form. She recommends "exploding" it by cutting and pasting, then Xeroxing, to get all relevant information in at the appropriate place.

"Anyone applying for a professional or high-level clerical job who doesn't spend at least 40 hours filling out the form 171, we feel, won't stand a chance," she says.

The competition for federal jobs is the result of a downturn in federal hiring since the peak days of the Great Society, as well as changes in federal job benefits and general economic conditions, according to Civil Service Commission officials.

The Civil Service Commission examines and rates most federal job applicants, but each federal agency does its own hiring. A number of federal job vacancies are outside the Civil Service System, in agencies such as the U.S. Postal Service, FBI, CIA and Veterans Administration, which have their own miniregisters from which they select applicants.

"We put out a lot of information at our federal job centers (over 100) around the country," said Arch Ramsay, chief of the Civil Service Bureau of Recruiting and Examining. "What happens is that typically aggressive people want to go as far as they can in getting job information. The newsletters obviously fill a void, or they wouldn't be selling. I suppose it indicates a certain sense of frustration."