I can't control it and like @Charbella am lucky if I get 4-5 hours/ night for years. I used to have to get up really early, now I have to work late, for a while I had to get up every 2 hours for someone else's care. In University I had insomnia. I never know what I will get, except that too little is horrid. I am getting better at getting back to sleep sometimes. The tricks I've heard are stand by your bed for 2 minutes (get cold), and the brain will see the warm bed as more inviting. Also try to stay awake in bed. Silencing all thoughts for a minute or 2 seems the key. No matter how awful I feel I try to say things I am thankful for, or in my case talk to a Higher Power (I call God). Also take Tylenol before bed vs when it's 4 a.m. and am still awake. Also there was a Navy Seal on Youtube who had a good short video (short muscle tensing and relaxing as a scan, happy place visual, plus something else at the beginning I can't remember? It was only about 2 minutes (his routine) ).