Active listening is a communication technique that requires the listener to understand, interpret, and evaluate what they hear. - Wikipedia
I'm surrounded by teens at least once a week, if not more, as my kids are notorious for bringing their friends over, using my house as a hang-out place or just a place they can come and be "themselves". Hubby and I are very open-minded and encouraging of our kids to look at all of the sides of a situation before accepting anything they hear or see as "fact" and their friends tend to enjoy that about being in our company. Doesn't hurt we have HD TV, high-speed Internet, a Wii and XBox 360, but I digress! Teenagers like to come over mainly because they can act and say what they feel without worry their parents, family members are going to judge them for their words.
Listen twice as much as you speak. It's crucial to be an active listener before you can be an effective communicator. Active listening means you don't just pay attention to the words thrown at you. It means you can listen without judgment. You take in the information presented and store it for future interpretation and evaluation but at the moment the words are received, you simply absorb. Become a sponge for the words and allow the person "venting" to really get their thoughts off their chest.
Active listening also means you don't offer opinion or rebuttal without asking if it's expected. When I talk to my teenagers, I always tell them "I'm going to listen as a Mother and a friend but I'm always going to respond to you as a Mother. Do you want a response or do you just want to vent?" Everyone deserves to be heard but not everyone expects a response. Part of being an effective communicator is making sure the other person knows what is expected of the verbal exchange.
Know your audience and speak to the audience. If a response is expected, if the person venting says, "yes, I want to hear your thoughts" then take a moment to gather your own thoughts and sift through the responses before vocalizing them. Having diarrhea of the mouth is never pretty. Take the information you've received and provide your opinion without malice. You may not agree with their viewpoint or thought process but saying "you're an idiot for thinking that" is not really going to help move the conversation forward. Instead, think about the person receiving your feedback and how they may interpret it. If you're unsure about that, simply ASK them! "Do you understand what I'm saying?"
My grandmother used to tell me people speak with their mouths but listen with their hearts. Is what you're saying touching their heart or skewering it?