Having one-on-one talks with anyone can be stressful, let alone having one with your teenager. Hopefully, my little guide can help you out in some tricky situations.
Make sure you and your teen are in a comfortable space. My advice would be to not have a talk in a public place, or in your teen's bedroom. Public places can sometimes feel claustrophobic, and while a favorite room of your teen's (such as his bedroom) is comfortable to him when he's relaxing, it can feel like an invasion if you try and have a serious talk with him there. Try talking in the living room, where things are open, warm and calm. Kitchens would be slightly less preferable, but if you have to move to there, that's okay too. Kitchens, while being the heart of the home, also generate a lot of heat, which can make for fiery tempers.
If you're a parent couple, try splitting up. (If you're a single parent, it's alright to skip this step.) After all, this is a one-on-one we're trying to have, not a two-on-one, although in some situations that's okay. Having both parents in the room can make your teen feel worse, angry, or ganged up on. Try and have his or her 'favorite' parent, the one he feels most comfortable with, talk to him in private.
Stay a few feet away. It's okay, for example, to put a reassuring hand on his shoulder, but don't get up in his face, so to speak. You want to give him the space he needs to stay calm, relaxed, and, once again, feeling as though he is not being invaded. Sitting on opposite ends of the couch is perfect. Getting an inch away from his face will, trust me, be counter-productive and result in anger and frustration. This lack of intensity will keep both parties calm and levelheaded, which is how you will achieve the results you want.
Keep your voice calm, but not patronizing. Nothing makes a teen more angry and upset than being talked down to like he is a child. I guess you could call it somewhat of a reverse psych move. By treating him like an adult, there is a greater chance that he will act like an adult. Be equals or peers in this conversation. Having an 'I'm older than you and I'm your parent so you have to do what I say' attitude will get both of you nowhere fast.
This one's kind of a bonus step. Hopefully so far all things have gone well and smoothly, but here are a couple extra little tips for keeping it that way during the conversation. If your teen starts to put up defenses, stay away from the word 'but', even if you say, 'I understand, but...' Go for, 'I understand where you're coming from. Maybe you could look at it this way...' It takes more breath, but it's worth it. 'But' equals 'forget what I said then, this is what I really mean,' and I don't think anyone wants to hear that.
When the one-on-one is done, make sure you remain friendly. Stand, say something like 'I'm really glad we could have this chat.' Avoid words like 'talk' or 'conversation.' It makes things sound serious, and that can ruin the relaxed mood you've worked hard on creating. Whatever you do, please don't be sarcastic! It's like one step forward, three steps back. Try to end with a hug, kiss on the cheek, and/or an 'I love you.' Don't be afraid to show your affection as a parent.
Well, I hope that helps you out a little bit. There is one last thing I'd like to leave you with as an all-around rule. Whatever you do, no matter what you're talking about, please, listen to your teen, and really mean it--don't just pretend to listen while you think about what you're going to say next! This is about your teen, not you. Well, it could be in some situations, but more often than not, it's about your teen! I think if you ask most teenagers, they'd say that they feel like their parents don't listen to them. Really listen when they speak and express their feelings. It will probably be the one thing that gets points across in the short run, and gets a stronger relationship in the long run.