''Be good at what you do, and you'll find a place to do it,'' advises career counselor Barry Gale, co-author with Linda Gale of ''Discover What You're Best At,'' a career discovery workbook (New York, Simon & Schuster, 160 pp., $8.95).
''People work about 80,000 hours in a lifetime,'' Mr. Gale said in an interview. ''Nobody should make a career choice just by listening to job market predictions. Careers are cyclical, like business. People should determine for themselves what they're best at. Good people in a field can get jobs,'' he affirmed.
Gale, who has had 12 years of career testing and is president and executive director of Career Aptitude Testing in Danbury, Conn., says his book deals with aptitudes, not interests.
''An aptitude,'' he explains, ''is a combination of innate ability and experiences. It's this nature-nurture combination - regardless of age - that gives people strengths useful for certain careers, while others have different strengths that make other careers better choices for them.''
''This doesn't mean that aptitude testing can predict what people will become ,'' he adds quickly. ''Tests are only as good as the interpretation of the results - but a person following the rules (in the workbook) can discover some careers which fit him.''
Gale thinks most careers are determined too haphazardly. ''A college student will send out 500 resumes and take the first job offered. That's not choosing, that's being chosen,'' he remarked.
Criticizing high schools for ''getting a kid ready for a job in a fast-food restaurant,'' Gale thinks most guidance counselors are chosen because they have good rapport with kids, but they may not have much knowlege or experience in the types of work beyond schools to share with their students.
Pressed to explain how guidance counselors without experience in the ''real world'' could help students make career choices, he advised utilizing consultants. ''Companies have an education or public relations department ready to help - they'll tell kids what to expect.''
''But not the career day format,'' he maintains. ''Speakers who are successful in their own careers may not be good presenters. When they ask, 'Any questions?' kids don't ask any, because the kids haven't learned what to ask.''
Invited to suggest some questions kids could ask such a visitor, Gale proposed:
* What did you do yesterday morning from 10 to 11?
* What is it that you don't like and assign your subordinate to do?
* What's your subordinate's title?
* What's the most satisfying thing that's happened to you in the past three months?
* Do you have to relocate to get ahead? How often?
* How often do you work late? Do you take work home with you?
* Could you leave your corporate position to start a business of your own?
Gale thinks questions like these emerge more easily in relaxed, round-table discussions, not in all-school assemblies. ''The college representative's visit is a good model,'' he suggested. ''But,'' he added, ''it's important to prepare for a career representative with some practice; students have to learn how to interview. Internships and apprenticeships are valuable, too,'' he said.
''No. 1 in making an intelligent choice is self-knowledge,'' Gale asserted. ''Then I'd say: goal-setting. Teach youngsters to set goals and how to reach them. Not all goals are career goals, but the process is the same. There's a lot of satisfaction from setting a goal and reaching it. You can keep a diary of what you do and write down which things you like.''
Asked about what families can do to help their own children make good career choices, Gale suggested, ''Use your connections to help your kids learn what's out there. Take your son or daughter to see where you work - and ask others to show them what they do on the job.''
Gale thinks commercial television isn't a reliable purveyor of career information. ''It's afflicted with a heroistic approach; it's not accurate. Police investigators solve crimes without getting blood on their hands.''
''The problem with newspapers and magazines (as sources of information) is that kids are not reading them.''
What are the popular careers with kids today? ''Communications, computers, and business (for the older students).''
''People need to be aware that different careers give different rewards: money, power, prestige, satisfaction, leisure, sense of accomplishment, opportunity for ownership.''
Although he has spent most of his time advising high school and college students, Gale believes two other groups are seeking career direction at present: homemakers who have an opportunity at last, because their children are grown, to seek an occupation outside the home; and midlife career-changers, who are recognizing they can find work that is more congenial than they're doing. ''It's important for these people to find out what they're good at - that's what really determines what they'll enjoy and succeed in,'' Gale said.
He said that at first he was surprised to be invited to address seminars at women's centers, but now he concludes that career direction for women is part of a large trend.
He feels his book will be as useful to career-changers as to those first choosing careers. It is based on clusters of careers for which an aptitude might be useful. ''There are 25,000 careers,'' Gale explained, ''and this book talks about a thousand of them. For some people the book will just confirm what they already know; for some, it will broaden the scope of their career opportunities; for others, it will narrow their focus. I think the word career comes from a French word for race track,'' he commented, ''and lots of people are running around that race track with blinders on. My purpose was to try to help them get rid of the blinders.''