Reader: My 17-year-old son is looking for an evening and weekend job. He’s polite, well spoken and clean-cut. But when he goes into places that are advertising, managers just tell him, “Apply online” (this includes the places that say “Apply Inside”). He has applied to dozens of jobs online and has not received a single expression of interest. It’s been tremendously demoralizing.

He has pointed out that it’s rare to see teenagers working even at fast-food joints or in grocery stores. Do you have any advice for him?

Karla: Polite, well spoken and clean-cut are a good start — but your son will need more to get a foothold in the current market. According to data compiled by Bethesda research nonprofit Child Trends, the number of high-school students with jobs has dropped from peaks of 35 percent in the late 1990s to about 18 percent in 2015. Child Trends research fellow David Murphey attributes the decline in part to automation and international competition, as well as teens’ increased focus on academic pursuits.

I suspect those first two trends have also pushed unemployed adults — willing to work for low wages, at any hours, exempt from youth labor restrictions — into some of the jobs traditionally filled by teenagers.

@Work Advice columnist Karla Miller. (Deb Lindsey/For The Washington Post)

But that’s not to say your son should give up. He just has to make an extra effort to stand out.

A study by the same nonprofit identifies the “soft skills” most likely to help youths succeed in the job market: communication, social skills, self-control, higher-order thinking and positive self-concept (self-awareness, not just self-esteem). The problem is that “those kinds of things are not visible on the Internet,” notes Kristin Anderson Moore, study co-author and Child Trends senior scholar.

Here’s how your son might display these skills:

Communication: Phone ahead and arrange for in-person conversations with managers at select employers. Business cards might be over the top, but a typed list of references wouldn’t be.

Social skills: Work existing connections with peers, teachers, family friends, clergy and neighbors. Parents can help make introductions.

Self-control: Fight discouragement. Keep busy, and keep looking ahead.

Higher-order thinking: Identify employers and personal connections where he’s most likely to succeed.

Positive self-concept: Develop and practice delivering a 30-second self-introduction: name, interest in opportunity, skills and assets.

The response might still be “Apply online.” But a manager might also remember the pleasant candidate who takes the initiative to personally introduce himself and who follows up with a thank-you message. And building those soft-skills muscles now will give your son a head start in the post-educational rat race.

Ask Karla Miller about your work dramas and traumas by emailing wpmagazine@washpost.com. Read more @Work Advice columns.

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PRO TIP: If you’re an under-18 worker or parent of one, check out the Labor Department’s Youth Rules website at youthrules.gov for information on the federal rights of underage workers.