Exercise regularly; I cannot overstate the impact this has
Cut out caffeine
Cut down on sugar
Take melatonin
Turn off your devices for the last half hour before bed - studies show the light fucks with your brain's sleep signals, even from your phone. Use this time to unwind, meditate, or read.
Go to bed at the same time every night
No TV in bed, train your body that bed is for sleep
I listen to a brainwave thing at night and I'm out in 3 minutes. I will PM you a link.
Re: Ambien, I would take great care to not get in the habit of taking something to get to sleep.