How do you teach kids to avoid any other yatzer hora? You shower them with the beauty of torah and mitzvos, and show them that you’re happy, even when you’re not; here and there you drop in lines about how we’re so fortunate, and that the goyim don’t have this beautiful torah…they spend all their time wasting away in front of screens and convince themselves that they’re enjoying life. Stressing over and over that something is assur doesn’t do the trick; it doesn’t work for lashon hora, tznius, bitul torah, or any other “biggie”
When I got into learning, I didn’t have a yatzer hora for internet, movies, etc…it was all empty and unappealing. If you get boys into learning, and girls into chessed, your work is 90% done.