With kids, interests change like the flip of a switch. And that is just as true with teaching them how to fly fish.
When young, they absorb what you tell them to a certain extent and then get distracted, so feed that distraction with some turtle or frog hunting.
When they hit their teenage years, place more attention on bugs, river currents or other nuances of fly fishing as their ability and willingness to pay attention increases.
From there, youth only get more independent. Send them on their way with a fly rod and some flies and wait for the stories upon their return. Sign them up for a Trout Unlimited camp or Expedition to feed their passion and learn about coldwater conservation.
If you’re willing to watch the change and revel in it, you’ll have a dedicated angler and hopefully a passionate conservationist on your hands in no time.