Hi there!
I try to eat a lot of food that contains tryptophan. I know the whole "turkey dinner makes you sleepy" thing is pretty cliché but I find that it really does work.
If I have a nice relaxing tea around the house like bono said above, that really helps. Teas that contain chamomile, lavender, valerian, passionflower, hops, kava.. etc.
Avoid caffeine a good 4-6 hours before going to bed. Exercising before bed helps too, with the endorphin release. Especially since you say you are a recovering heroin addict, exercise would be great for the lack of endorphins in the brain.
Or masturbation lol... I find that actually helps a tonne when I have insomnia. As awkward of a topic that could be for some people, it is a good way to release endorphins if you are trying to sleep.
