Tip - Observe their Friends and Any Absurd Behaviours

They say all sorts of substance abuse begins as a teen due to the increase pressure in peer influence.  From the beginning try to develop a trusting relationship with your kids, so they may share with you the kinds of friends they meet or befriend. 

From child when they try to hide something from us, we can tell by their behaviour or facial expression. Well, guess what the same applies when they reach their teenage years.  If your daughter never locked her door and all of a sudden she begins to lock her door, then it is a big alert sign. Keep eyes on the back of your head.