The book Why We Sleep by Matt Walker is very good.
Preparing for sleep starts as soon as you wake up. Get outside for at least 10 minutes first thing in the morning, even if it's cloudy.
Spend as much time as you can outside. It's the brightness of the light that you need first thing to trigger sleepiness 12-16 hours later.
Do some exercise, physical tiredness helps.
Have your last meal about 3 hours before anticipated bedtime. If you feel hungry before bed (I used to) try a hot drink.
In the evening keep the light around you as dim as you can get it and as red as you get it to trigger melatonin release. (This difference between the bright light of morning and the dim light of evening is important). Make sure any screens are as dim as you can make them and use the red-shift functions if you can.
If you're woken up by your bladder overnight try focussing on hydration during the day, then switch to small sips after your last meal 3 hours before bed. (This was a gamechanger for me!)
Have a bedtime routine similar to what you'd do for young children: check the doors are locked, wash your face etc, take any medication (also worth checking whether medication has potential for sleep disruption), read a book (with a dim red light). Remove any visible clocks.
Make sure your bedroom is very dark and cool.
If you wake, it's no big deal, read your book, potter downstairs if you can't fall asleep quickly.
If you have a poor nights sleep get up at normal time so you don't push your sleepiness back at the end of the day. Yes you'll be tired for one day, but your next nights sleep is likely to be better.