Surprised nobody's mentioned it in this thread yet, but Matthew Walker's Why we Sleep [0] is a great in-depth look at sleep and how complex its interactions with our day-to-day routines/quality of life are. It has a lot of practical advice on improving it, most of which is summarized here [1].
I went from a varied sleep schedule, trying to catch up on the weekends, etc to a solid 7.5-8h routine every night and it's made a tremendous difference. Best of luck to you!
I enjoyed the term 8 hour sleep "opportunity", that he uses. Much more relatable for me.