Conventional wisdom is to keep a balanced circadian rhythm. Sleep at regularish times. Your body clock is set by when you first see blue light from above, so going outside first thing and looking up. Meal times too. Consider your diet and pre sleep habits - sugar, tv, caffeine tend to mess with sleep. Alcohol disables your adrenaline and helps fall asleep but then lowers the quality. Weed largely removes dreams and helps feel rested, but then there's a slight hangover that encourages you to keep smoking
In short, it's a holistic lifestyle thing. Everyone is different, so keeping a journal and experimenting helps. And of course your daily level of stress is a factor