Great question Shil1978 -I agree with aplagirl
If I may add...
I have a teen at home and I teach middle school. I think the most important thing is letting them know that they have a voice. Many don't realize that we value their opinion. This is why many teens shut down. Yes, they do need their space and you have to gauge when to approach them, but a slight nudge or prompt does wonders. They may not feel like talking at the time, but saying something like, 'rough day? We can talk about it when you are ready' opens doors for later in the day. You can prompt them again later on, 'ready to talk about it?'
Teaching teens about point of view does wonders as well. They will begin to realize that different perspectives are ok and that we need to acknowledge opposing opinions - respectfully. Conversations of, 'why do you think that way' help them realize why a parent says or acts the way they do and vice versa. The earlier these lines of communication are open - the better. Plus, teens need to realize they cannot control every situation.