Traditional WILD technique stresses laying in bed until you fall asleep.
But it's very hard to implement it for a typical "coach potato" type of kid or adult.
Think about it - almost none of us perform heavy physical activity, walk long distances or otherwise tire their body through the day.
Minimum physical exercise results in you being not tired = trouble falling asleep.

On ld4all, I've read it takes on average 8 minutes for a person to fall asleep. I dont know if this information is correct, but there's a great chance it is...

As a result, some people report very easy WILDs, while others (like me) have great trouble falling asleep