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How to deal with teenage insomnia
Don't drink things containing caffeine (coke, coffee, tea) at least three hours before you go to bed.
If possible, cut out caffeine as much as possible, like drinking decaf tea.
Don't go to bed hungry, but don't stuff yourself.
Have your evening meal at least three hours before bed and have supper if you are hungry. Make sure the bedroom is dark when you go to sleep and light during the day.