I recommend a slow but unvarying bedtime routine that you can stick to whatever you’ve been doing earlier. I feed the cat, turn off the main lights and put books etc away. Then I go upstairs, open the windows, undress, go to the loo and take my pills. After that I water-floss and then clean my teeth. I then choose what radio programmes to play on BBC Sounds as I’m falling asleep, plump the pillows and shake the duvet. All that takes about half an hour. I set my sleep monitor, lie down in my most comfortable position (right side, high on pillows, pillow under upper leg) and lie absolutely still listening to the radio. As often as not, I’m asleep within 10 minutes, but if not, after the first radio programme ends, I turn over to the other side and start a news programme (PM or The World Tonight). I never hear the end of a second programme.
I do this whether I’ve had a full working day or a day doing nothing, whether it’s 9pm or 1.30am, and whether it is hot or cold, noisy or quiet, and it always works.