i was always shocking at getting to sleep, would read till all hours and it would regularly take me more than two hours to get to sleep so I'm trying to think what would have helped me as a child. I actually only became 'normal' at getting to sleep when I met my XH and realised that it's actually possible to fall asleep within 10 minutes of going to bed. My problem, and I think your DD's problem, is that she can't switch her brain off. I see the same trait in my DD2.

What helps me on the rare occasions now when I'm having difficulty dropping off is some half-arsed meditation. I know enough to know what I need to go to sleep. Usually, I tell myself something like, "whatever I'm worried about, I can worry about it tomorrow." or "I accept that my life is not perfect at the moment." I'm not saying that you should teach DD those things but maybe something like, "it's time to stop thinking now, relax, think nice thoughts and go to sleep."

I've had a quick google and apparently there's podcasts that you can download for children. Like anything, there's probably good ones and shockers so if you're interested, it might be a bit of trial and error. I know that I always found the sounds of the rainforest, visualisation-type ones intensely annoying and irritating!