Things that helped me to get to sleep easily, maybe some are universal.
Determine how much time do you need to be ready to sleep, and start preparing at that time + desired sleep start.
Avoid taking serious doses of caffeine at least 8h before sleep. You may not notice effects while awake but sleep can be still disturbed.
If you are sensitive to light, sound, temperature, etc, ensure there will be good environment at least in first 2h. Temperature will fall after you stop moving so leave it a bit warmer.
Most important thing is not moving at all. Lie down and focus on your body to determine if you are comfortable. If it is, fix that position and do not move at all. If serious problem is found, make a single decisive movement or repeat setup, but don't just flail around (anxiety can temptyou to do so)
Breathing is linked to mind state, so if you have disturbing thoughts, feel free to think them but focus on breathing deeply and slowly (2s inhale, 2s keep, 2s exhale works for me). After a while thoughts will align.