Dont watch tv, use phone, or computer for at least an hour before you want to go to sleep. This allows your brain to slow down and get ready. If must use pc, or phone I recommend getting flux its an app that removes some of the blue light from your screen. In that free time take a bath, read a book, or w.e relaxes you.
Using a computer or phone won't work for me, computer makes me use internet and do lots like surfing or watching porn and phone makes me use instagram or apps…