I don't have a cellphone at all. I also read the book "Sink into Sleep" by Judith Davidson, a clinician at one of the hospitals here in Canada. Part of the technique is figuring out how much real sleep you get and what time you wake up regularily now. ie. 4 hrs. of sleep...then don't go to bed so early. I know, but the point is to make yourself truly tired and then go to bed. There is some rigour to all this at the beginning to make it work.
And all the techniques to make me sleepy naturally --warm milk, a few hrs. later herbal tea (for vice versa) and doing non-stimulating things for the mind-- reading a book (not an e-book). That's why no computer exposure....my doctor told me to get off because I'm in front of a computer for over 80% of my full time job.