My entire life, but especially in graduate school, I've had horrible sleep. Both falling asleep, and staying asleep.

I did multiple sleep studies, used sleeping medications, took supplements, tried to meditate, etc. and had no luck.

I went and did CBT-I, where they had me change my sleep hygeine (all your standard recommendations of "no TV in the bedroom", etc). But the biggest thing was they had me start off by going to bed at 1 am and waking up at 5am every day for a week or two. I'd be so insanely tired, I would start falling asleep quicker and staying asleep less interrupted (this was recorded on a worksheet). Then they had me go to bed an hour earlier, record it. After a while, we found my optimal schedule (bed at 11am, wake up at 630am), and I stick to it no matter what, every single day.

It's solved my sleep issues, full-stop. I get tired by 11 pm, and wake up at 6:30 am feeling just fine.

FWIW, grad school - with no solid schedule - was disastrous on my sleep. Moving to my 9-5 corporate job has made scheduling my sleep a whole lot better.

Just my experience.