If you don't completely succeed, try again," declares Matthew Shannon, head of the D.C. Summer Youth Employment Program. "I think the public is tolerant and supportive of leadership that recognizes its mistakes and is willing to try again."

That, in a few words, is the philosophy of the man who headed the city's summer jobs program two years ago, was booed for some of the unhappy results and who, despite his previous experience, is ready to try it again.

Shannon says he has spent a lot of time during the past two years thinking about what went wrong with the summer jobs program in 1979 and again last year (under another administrator), and how to fix it.

"I'm really up for the challenge of making sure that the program doesn't have the problems that it has had in previous years," Shannon said.

On June 23, the day the summer jobs program begins, an estimated 18,300 young people, ages 14 to 21, from low-income families are scheduled to go to work for a variety of city and federal agencies and community-based organizations. Private industry in the city will provide an additional 1,200 jobs for total of almost 20,000 jobs -- about 2,000 fewer than were available last year. The District has an estimated 50,000 teen-agers.

The $8.6 million program, paid for by city and CETA funds, is aided by the Greater Washington Board of Trade, the National Alliance of Business and local chambers of commerce. Young people are put to work for eight weeks as secretaries, clerks, errand runners, receptionists, researchers, playground assistants and groundskeepers. Most of the youths will earn the minimum wage of $3.35.

Shannon, who admits to a few sleepless nights as the opening day of the summer jobs program draws near, set forth his strategy for avoiding problems.

"First, the registration deadline. Last year," he said, "the young people could register up until the first day of work.

"This year, the deadlines was May 31st," he said. "We cut off registration early enough to make sure the information we have is correct.

"Second, we have visited the work sites where the youths will be working and we have confirmed that all of the jobs exist and the work will be meaningful.

"Third, we have identified programs for 14- and 15-year-olds to bring up their basic skills so they can compete in later years for meaningful job opportunities.

"And we have put together an automated payroll system which will allow us to build a systematic master file. So we can be sure that the paychecks are written, that the people receiving the checks are valid workers and are being paid the correct amount for the hours they have worked.

"The major difference in this year's program," Shannon said, "is that it has been a very orderly, manageable approach."

But the key element, Shannon said, is a new computer program to keep track of the summer jobs and the workers. He acknowledges that perhaps the biggest threat to a smooth-running operation would be a computer breakdown.

Gone, Shannon says he hopes, are the days when 30 percent of the youths who registered for summer jobs registered more than once, so that many jobs were not filled and several hundred youths collected two paychecks while working at just one job.

Gone, too, he hopes, are the protests and demonstrations by angry young people whose paychecks came late and sometimes not at all, the days when many youths started working three weeks behind schedule and the days when workers complained "there was nothing to do" and played cards, shot craps or talked instead.

While Shannon willingly takes the blame for his 1979 troubles, he makes it clear that he got the job late, starting in February of that year. "I came into an office (at 500 C Street NW) with no files, a completely empty office. I had to completely reshape the operation, give direction and reorganize the staff," he said.

"And on top of that, I had a commitment to fulfull for the Mayor (Marion Barry) because during his campaign he said he was going to hire 30,000 young people for that summer. Heretofore, the largest number the government had served was 15,000. On the 21st of February, there was nothing in the way of planning for those 30,000 young people. No registration, no job development, no referral process, no computer system, no payroll system, no anything."

In 1979, Shannon's own staff criticized him for his strict management style. "People said that I was very rigid and unwavering in my commitment to hire 30,000 youths," he said. "The payroll processing staff (seven workers) decided they were going to walk out. So they turned in their resignations. I accepted them all and replaced them with new workers. They were trying to stop the program. That couldn't be tolerated."

Shannon said that 31,000 young people were on the payroll that year, despite the problems. He was succeeded last year by John M. Anderson, program director of the summer jobs program. He, too, encountered major management problems.

Shannon, a robust 31-year-old bureaucrat, has served as an aide to Mayor Barry on labor and religious affairs between two tours in the city's labor agency. Last October, he volunteered to return to Department of Employment Services (DES) as deputy director of the program operations division, a title which carries with it the task of directing the summer jobs program.

During his previous tour there in 1979, he held the rank of acting director and was also responsible for the jobs program. After Shannon left the agency, then called the Department of Abor, it was renamed and reorganized.

Last October, Shannon was contemplating a move to the federal government but Barry asked him to stay and offered him his choice of three jobs -- in the D.C. Department of Recreation, the Recorder of Deeds office or the labor agency.

He said he took the labor agency job because he watched last year's difficulties with summer jobs and thought to himself: "I've got to go down there and help in some way."

Shannon now holds a DS-15 job which pays between $42,874 and $50,112 a year.

Shannon, who grew up in Pleasantville, N.J., transferred to Howard University from Tuskegee Institute and attended Howard from 1968 to 1974 as an undergraduate and later as a law student. In 1976, after working in a law office in New York City and an insurance office in Connecticut, he returned to Washington and set up a law practice on 12th Stree NE in Brookland. He lives in Brookland with his wife Shirley, a D.C. public school teacher, and their three-year old daughter Tiffany.

He was active in "the student concerns of the day," Shannon recalled, including a stint working in Robert Kennedy's presidential campaign. Later, he campaigned for former mayor Walter Washington, Del. Walter Fauntroy and Mayor Barry. In recent years he has run for the D.C. School Board and the City Council. He lost the school board election and an automobile accident curtailed his council campaign.

"The whole concept of the summer jobs program is to provide (disadvantaged youths with) an introduction to the world of work as well as provide them with a meaningful work experience," Shannon said.

"As with any job of great difficulty, the rewards in the end are very great. If you can think of the outcome, it always makes the job a lot easier. I always think of all the young people who will be working as a result of my efforts," Shannon said.

One man who has worked closely with the summer jobs program is Rick Sowell, executive director of the Adopt a Neighborhood in Renaissance Project at the Crispus Attucks Park of the Arts at 38 V St. NW. The nonprofit community-based organization hired 466 youths last year.

"The first three weeks on the job is dedicated to breaking through the youths' apathy aura," said Sowell. "The youths are apathetic about the system. They come in expecting to be hustled about their paychecks. We tell them point-blank that there is a possibility of them not getting their checks on time. We tell them how the system works."

The Adopt a Neighborhood Project, which has won two U.S. presidential youth awards, combines business development, art, music, education and community activism. The Project is waiting for the DES to approve a "special technical music project" proposal for this summer that would involve 1,300 youth workers, including several entire high school bands.

Sowell said, "We've always tried to have a good program, but dealing with the (DES) has never been a positive experience. The summer's here and our proposal still has not been approved. It doesn't look like anything's changed."

Shannon responded that Sowell's proposal for the special project, although promising, was denied this year because, among other reasons, "the use of school resources and facilities has not been officially sanctioned by the board of education."

Jerrily Kress is chairman of the Washington Board of Trade's Summer Job Bank, a volunteer program that encourages private businesses to help put thousands of youths to work. Whether the summer work experience is in the public or private sector, the basic concept remains the same, she said. "Most people's first summer job is not in the field that they're in now. It teaches you how to act in the real business world. It gives you a forum in which to make mistakes," Kress said.

Kress, principal owner of the Kress, Cross and Associates architectural firm, said that summer workers often bring a contagious excitement to the job. "From the employer's point of view, when you bring in somebody who is younger, it makes the younger people that you have already in your organization respond. It inspires people to set an example for the younger workers and that's a positive thing."

Kress said, "A young person's greatest asset is attitude. Lamost anyone is going to respond well to someone who wants to learn, who wants to try and who is positive."

But young workers are bound to encounter special difficulties on the job, especially if their supervisors don't explain things to them clearly, Kress said. "I think that young people sometimes expect too much. In the educational system you are told to find yourself and what you want to do. Gwhen you get out in the real world, you're told to go out and run an errand for the boss. Many youngsters may think that that is a putdown, that they're not worth too much. But what they don't realize is that that's where all of us started. The supervisors have to say that."

Carver Leach, director of the D.C. Department of Recreation's Roving Leader program, said, "Many adult supervisors in the private and public sector don't know how to communicate with youths. They have a boss syndrome. They don't want the youths there to begin with and, to add to that, they don't address the youths with the proper respect. Young people are sensitive. They treat them as if they're doing them a favor. That's when the youths develop attitude problems. Tardiness, unwillingness to work sets in.

"That's unfortunate," Leach said, because "the majority of youth in the city are good, they're responsible and they're eager to work."

Seteria Johnson, a vocational specialist and counselor for the Southeast House Manpower training program, works with some of the city's most disadvantaged youths. "There are quite a few youths who are sharp, progressive, motivated and energetic. It's a pleasure to be in their company," said Johnson. "But most of our youths' job performance varies day to day depending on how much stroking they get -- such as telling them, 'You look good today,' or 'You're doing a good job.' Just recongnizing their existence is a stroke in itself sometimes."

The Manpower program employs youths as hospital aides, community service workers, administrative adies, peer counselors, and carpentry and electrician trainees, Johnson said.

"There are a lot of low-income young black males in the program. They know that they represent the group with the highest unemployment rate. So they are mostly eager to learn a trade. They really want to be albe to go out and get a good job. Sometimes they tend to be overly aggressive, impatient and easily descouraged," Johnson concluded. Working at Pool

Antoine Jones, 21, grew up in the District's summer jobs program. He worked for four consecutive summers, then parlayed his experience into a part-time, year-round job with the city.

In 1974, Jones, then 14, got his first summer job as a day laborer with the D.C. Department of Environmental Services.

"We swept, raked, cleaned alleys, picked up beer cans, pushed brooms, and cleaned streets. The job was pretty nice, but it was burning hot after 2 p.m," he recalled.

He worked for environmental service again the following summer, but the summer after that, he said, "I wanted an inside job. The sun was getting too hot." He got a job as a swimming pool, locker room aide at the Mamie D. Lee public school for handicapped children in Northeast.

He worked there another summer in the same capacity, then was asked to work throughout the year for four hours each day after school. Eventually, he worked his way up to a higher-paying job as a year-round lifeguard. After graduating from McKinley High School in 1978, he began working as a lifeguard at Dunbar High and Shaw Junior High schools and a diswasher at a Hyatt Regency.

Jones, who lives in Southeast Washington, hopes to attend college someday, and major in special education. He will work this summer as a lifeguard and supervisor at Dunbar and Shaw schools. Looking Elsewhere

James Yarborough, 19, was discouraged by his summer job experience last year, he says, and does not plan to participate in the program this year.

For the last two summers, he has worked as a maintenance crew supervisor.

During the first summer, 1979, he worked for Pride Inc. The following year he worked for the Department of Employment Services Manpower agency.

"The first summer, I kept time and attendance and made sure the workers did everything they were supposed to do," he said.

The workers cleaned streets, play-grounds and buildings in Northwest and Southeast, said Yarborough, a 1980 Cardozo High School graduate who is now a freshman at the University of the District of Columbia.

"We were really helping the community. It was really good because it was like a learning experience and a group effort."

However, things changed last year, he said.

"Last summer, a whole lot of people didn't get their checks when they were supposed to get them.

"The people who were supposed to be in charge didn't put us to work. It was really an unorganized program. This summer, I won't be working because I don't want to go through that again. I have other plans. . ."