I've had a lot of sleep problems in the last few years, but I think it's because I have to get to bed at a decent hour since I'm a mom.
Previous to my child being born, I was a severe night owl. But then I'd sleep late into the morning and not be productive during the early day.
In order to sleep well now, I need a good amount of exercise and plenty of time outside. And I need to stay away from screens...computer or TV...for several hours before bed.
I have been diagnosed with attention deficit also, and stimulants work strangely with me, often making me very sleepy, but having the opposite effect when they wear off. Half an hour after coffee or my old prescription stimulant medication, I was good for a nap. So in general, I need to pay attention to any form of extra stimulation in my life, including too much or too little excitement during the day.
Meditation has helped, as does keeping my house and life running smoothly. If I let things slip, I get angry with myself and a very vicious cycle starts, including insomnia.
Menopause was also mentioned...I've gotten some relief from oral contraceptives, which I restarted for a variety of reasons including insomnia. I know that hormones can play a huge role in sleep.
If I fall asleep well, I know that I am taking very good care of myself.