Follow Through
It's so much easier to say than to do. You tell her what the consequences will be, and then she still doesn't back down. Suddenly, you're faced with your own struggle: do you back down or follow through? The answer is key to your success in raising her.
Often times, parents will toss out a possible punishment without thinking it through themselves. “If you don't clean your room by 2 P.M. you will
And what if the punishment really makes you sad? Let's say your daughter has been back-talking and misbehaving. You've been waiting for her new cousin to be born. But the day before, you say something like “If you speak to me that way again you'll go nowhere for two days!” She speaks that way again, and guess what: you're in a position to keep her from a moment that was going to be truly special. Can you back down? Some might say yes, but consider this: you want to raise a girl who understands responsibility and true consequences. If you carry it through, it might be disappointing, but she'll learn a valuable lesson.
Essential
Make a list of possible punishments. Write them down and refer to them. By planning ahead, you may avoid blurting out something you'll regret later.
She's misbehaved to the point that you need to restrict her from everything: cell phone, TV, nights out, and yes, this is the week of the big freshman class trip. You gave her every chance to change her ways, and she did not. Feeling bad for her, sadly, is no reason to back down. But that does not mean you cannot feel bad for her. While the event she is missing (and will never happen again) is going on, talk to her. Tell her how disappointed you are that she is not there, and how you hope you can both work together to find a way that this never happens again. And what about bargaining? She might say, “If you let me go to this, I'll stay in two more weekends.” It's best to stick to your original punishment. She'll learn: that's life.

