My kids are all night owls, which means they tend to gain energy as bedtime approaches. To help them calm their bodies and minds, I started a simple nighttime relaxation technique with the older two. My nine-year-old appreciates it the most and will ask for it nearly every night. Mikko and I both have the characteristic of needing a looong time to fall asleep, and he can get anxious about it. This sort of relaxation time helps put him at ease.
If you already have a background of relaxation scripts, you can adapt ones you love. I called upon my own childhood, when my parents offered me some simple relaxation ideas when I kept stealing into their room each night to whisper that I couldn't fall asleep, and my experiences with Hypnobabies childbirth hypnosis, which helped me through three unmedicated births.
Have your child lie down and begin in a calm, soothing voice:
Squeeze your toes … and your feet … and your legs … all the way up to your bottom [or whatever word you use; we're a butt family].
Have them practice isolating each muscle in turn. Mikko has coordination difficulties so at first had to use his hands to assist him in highlighting each body part to contract; however a kid needs to do it is fine.