Don't watch tv or use any kind of electronic device 2 hours before bedtime. Try reading magazines or fun, age appropriate books until you fall asleep. Do you have too many things on your mind or are you worried about something? If so you should see a therapist about it.
Digital electronics emit light via the screen that confuse the brain to presume that it is still daylight thus preventing you from sleeping. You need to go jogging at night then read a book and you should knock out pretty quick.