Hey, glad you asked that, I struggled a lot with this in the past.

• Go to bed at approximately same hour (1 hour late/earlier, same hour)
• Force yourself to wake up at the same hour (very important)
• Do this for 2 weeks and your body will adjust
• If you can't sleep, take melatonin. Melatonin helps control your sleep and wake cycles. For more benefits , check this article here : Melatonin Overview
• Rip the benefits of feeling great and having more energy by doing the things above

Will probably dedicate an article on this subject.

Good luck !