Read a book
My toddler knows best in this regard. We often ask him what he would like to do before taking a nap or going to bed. His response is regularly the same: “Read a book; take a nap.”
Reading before bed generally is a good way to put oneself to sleep. I’ve been working on the first half of “A Dance with Dragons” (5th book in the A Song of Ice and Fire, aka Game of Thrones) for over a year now. Part of that is to do with not reading fiction books as often as I should but also to do with the fact that I fall asleep shortly after beginning any reading session before bed. The other part is that I just don't read as much as I should. I tell myself I'm going to, but "reading" on my phone is a lot easier to start, and regardless of how useful it is, it is easy to sucked into the consumption of information.
In order to help with the nightly routine adjustment, set a timer for yourself for how long you use your device. When the timer goes off, switch to a book if you'd like to continue reading. Make sure the timer goes off at least an hour before your ideal bedtime. As you get more used to it, set the timer earlier and earlier. Stick to the timer like it's the law.
Reading an e-book on a phone or tablet does not have the same effect unless I do it on my 1st gen Kindle with the e-ink screen. There is no backlight and the screen is almost as relaxing on the eyes as the real deal. Again, avoid reading on smart phones or tablets before bed. See previous posts in this series for that.