Allow the teenager some alone time with minimal monitoring. This will help raise the trust levels between you and the teenager.
Talk to the teenager once in a while about your childhood life and things you did as a teenager. Do not leave out mistakes you did growing up which you regret about. Also mention the bad choices you made and how maybe youd have m,ade things better. This gives teenagers a sense of reflection and self thought during that alone time.
Allow the teenager enough rest. Otherwise, the emotions portrayed by the teenager will be violence, anger and aggression.
Never ask a teenager to be like... maybe a friend's child. This will slowly destroy the relationship since it shows how much you wish they were better.
Just make the teenager feel okay with whatever he or she is doing but constantly remind him or her there is room to improve.
All teenagers need nowadays is regular gestures of support, love and motivation.