One of the ways I do this is “spot the lie” when an ad comes on. Virtually every ad has some lie in it, even if it’s small. Buying this brand of car will make a sexy person like me (nobody cares what you drive). Altria Group is altruistic (they kill millions with cigarettes). Adopting a pet today will make you happy (Not everyone can care for a pet, and sometimes it’s miserable). A price of $4.99 is basically $4 (it’s really $5). I practice this, talking about why the ads exist and why they are effective, the biases they tap into. Everyone is vulnerable to manipulation like that. And then I extended that to some of the videos my kids watch. Why are the Ninja Kidz playing with that toy the entire episode? Because they were paid to do it. It’s just another ad.
Then that skill pivots to other things. Religion behaves the same way, selling itself to people. Conspiracy theories do this as well. And sometimes other people are doing the advertising right to your face, and they may not even realize it.
In short, equip your kid with the best BS detector that you can, and then let them find their way.