My oldest daughter is turning 12 at the end of August and I am finding that her mood swings and attitude are getting worse. I understand that it is her age and things are changing unfortunately I am quite a strict person when it comes to the attitude that happens in my house. She is constantly fighting with her younger sister (only when my husband or myself are home), and she is lying constantly. About silly stuff, eg..whether she brushed her teeth or not. I don't know how to talk to her without destroying these very sensitive years.. But on the other hand we butt heads everyday. How do you suggest I talk to her? Any advice will help... Thanks in advance.  

I cannot tell you how often I hear this, especially with girls.  It is a strange phenomenon when your sweet, affectionate little girl is replaced by a sullen and angry imposter.  It's important for you to understand two major realities: firstly, your daughter's adolescent brain is simply under construction and the hammer is wielded quite crazily during these years.  Her frontal lobe, which houses her ability to have perspective, is not fully developed.  The second reality is that even though I know it's incredibly difficult to do so, it's paramount for you to work at not taking anything she does or says personally.  Trust me, she does not want to hurt your feelings.  She just doesn't yet understand her own. 

I assure you that your lovely daughter is still in there behind the mood swings and all that attitude.  At this juncture, you need to try to do the best parenting you've ever done and it will not be easy.  When your daughter lies or acts out either with her sister or you and your husband, it's a sign that she's dealing with attachment issues.  She is feeling the need to be independent and pull away.  It is much easier to do this with people at whom you're angry.  Try not to take this personally because if you do, not only will you feel bad but your reactions will cause her rudeness and dismissiveness to escalate and before you know it, you'll be stuck in a very bad cycle that can become much, much worse. 

If being very strict and butting heads was going to work for you, it would have done so already.  Rigidity and adolescence though, are often a recipe for a minefield.  Just as you want your daughter to change, you may want to try for a little bit of elasticity in your expectations, in your strictness.  Teens need and want close relationships with their parents.  The protectedness they feel helps them with self-esteem, making good choices and saying no to unsafe behaviours.  When these kids feel continuous disconnection from their parents they will orient more to their peers who are also feeling disconnected and the situation becomes a lot like lemmings leading lemmings.  It's critical that you first find ways to reconnect with your daughter -- laugh with her, make her feel loved and understood in your home.  When she is rude to you, being loving may feel like the last thing you want to do but her behaviour will not improve otherwise.  Tell her stories about funny things she did when she was a baby.  Show her old pictures or mementos you've saved.  Leave little notes for her and let her come to you in her own time.  If she rejects your efforts, know that she's only doing this on the surface to save face.  Inside, she will feel happy and soon you should notice her behaviour coming around.

Let your daughter know how loved she is by her family.  Adolescents need to be told and reminded of this even though we may not think they want to hear it.  She may know she is loved intellectually but chances are, she also knows she isn't behaving in a very lovable manner.  She needs to know you're there for her no matter what.

You will have to use unmined resources of empathy and understanding.  The mirroring technique I discuss in my book is a fantastic way to talk to teenagers.  It will increase compliance and bring out the best in both your daughter and yourself. 

Once you've repaired and strengthened your bond with your daughter, you can then balance that with being firm and setting limits.  Critical here, is staying firm but fair, and always neutral in tone.  Advise her of the consequences if she reverts to being rude or disrespectful and if you need to, follow through in a calm way. This way she will learn that she is responsible for choosing natural consequences based on her behaviour.  If you start to butt heads again, your daughter may perceive you as too harsh or mean and focus all her attention on your behaviour instead of on her own.  She needs to walk away from all interactions with you feeling loved and understood even when her behaviour is disappointing.  When you follow this recipe, it shouldn't take long for the negative behaviours to disappear.  She will start to show her best and will be well on the way towards handling anything life throws at her.  Always remember, it's the child with whom you least feel like being empathic who needs it the most.