Sounds obvious, but lay off the calories in the last 3 hours before you go to bed. The last thing you need for a regenerating night’s sleep is for your body to have to metabolise a whole load of food during the night.
In my experience, overeating before I go to bed makes it harder for me to get to sleep in the first place, and when I do finally get to sleep I find myself dreaming like a neurotic idiot.
In summary, if you don’t eat too much before bed you will thank yourself in the morning. Your hairline will also thank you!