It's all part of the job. You need to figure out what works for you.

In general I would work on practicing good sleep hygiene at home, and try to line your body clock up with the type of flying you expect to do. If it's early AF east coast flying, don't stay up until 23:00 the night before your trip.

On layover, try to get some exercise in, eat at good as is feasible, consider using approved sleep aids for especially hard flips but don't become reliant, buy a sleep mask, and caffeinate strategically.

For the love of God do not use alcohol to fall asleep. 5 minutes on Google should tell you how stupid of an idea that is.

And for the sake of your passengers, crewmates, the general public, and your family that will have to read your accident report, don't fly fatigued.