1. Force yourself to get up two to three hours earlier than usual. Then immediately get some sun. It signals your body to stop producing the sleep hormone melatonin. So opening your curtains or having breakfast outside can help you adjust.
2. No caffeine after 3:00 PM. That means coffee AND soda. It might not matter for everyone. But people in the study had a three o'clock cutoff time for caffeine.
3. Keep lights to a minimum at night, and get in bed two or three hours earlier than usual. It trains your body to start producing melatonin earlier, so it's easier to sleep.
4. Stick to your schedule. Don't stay up late, or sleep in on weekends. For the first month or two, try to go to bed within the same 30-minute window each night. And naps are okay, but not after 4:00 PM.
5. Move up your meals. Have breakfast as soon as you wake up. Don't do dinner after 7:00 PM. And you might need to shift a few other things too. Like showering earlier, or exercising in the morning instead of at night.