I had trouble sleeping most of the time from about age 13 to 29. I more or less went through the same process as the author and discovered CBT for sleep is incredibly useful - this is what worked for me more than anything else. Since then I maybe have a poor night of sleep once a month at most. Ultimately, just calming down and letting sleep happen is what is going to fix sleep problems for those who are anxious about sleep (which it sounds like you may be) and this is a hard thing to learn when you're in that sleep anxiety mindset. Highly recommend CBT for sleep.