What needs is she trying to meet by this behavior?
Is there a hidden cry of her heart?
This is a training issue. And it is a relationship issue.I have been through this with all three of my kids. Yes, I have walked out with a screaming kid, out of stores, museum exhibits, restaurants, parks, I have been there. But now everywhere I go, people compliment me on my children.
Are you setting expectations with her in times of non-conflict?
Before going to a store, when all is quiet, in a firm and gentle voice:
"Jane, we are going to the store now. Here is how we behave in stores. We walk quietly until Mom is done shopping. You hold my hand. I will not buy you anything."
If she starts to throw a fit, calmly say, "we are leaving now because you are throwing a fit." THEN DO IT. Follow through is essential. Staying calm is essential. Say nothing more, just leave and go home. No threatening, no repeating, no blaming. You must remain in control because she will test you.
She (and you) need to be very clear about what is expected before you go anywhere or do anything. In fact the first time, make sure you don't really need to go to the store and keep it really short so that she can have success. You want her to succeed! Praise her for fantastic behavior! She needs to hear that you noticed her good behavior and your praise is her reward. Report her good behavior to others while she is there. Each time you go into a situation, briefly, calmly review your expectation of her before the fact. Look her in the eye and tell her lovingly exactly what you expect her to do (leave out threats and leave out any mention of bad behavior).
You must master walking into a store, calmly buying your things and leaving. Only then, can you go to the next step. "Jane, I have noticed that you are getting really good at going to the store with Mom! Last time we went I was so proud that you walked with me and we got my stuff. We are going to the store again today. Is there ONE thing you can think of you'd like to get?" It's one thing. If she can't think of something appropriate, suggest a choice between 2 things you are willing to get and you know she likes. Review the expectations. "Jane, we're going in now. I will get [your thing] at the end of our time. I need you to [remind her briefly of your expectations] and then we will get your thing."
It is SO IMPORTANT to stay positive and act like you expect her to act this way. And to calmly walk out if a fit is thrown. You are calm and in control of the situation. Don't make your actions dependent on what she does. Don't try to reason with her while she's in a fit. Just train her in calm times and talk about your expectations. If you stay calm, she'll eventually stay calm. If you are polite and positive to her, she'll feel more secure.
SAY NOTHING if she throws a fit except, "We have to leave now, because you are throwing a fit."
Mouthy behavior is the same type of process. "Jane, do not talk to me that way. It is not right." But ask yourself, "Am I treating my daughter as I want her to treat others? Am I talking to her in a way that lets her know I love her? How is my attitude toward her?"
When I was having issues with #2, a mentor of mine asked, "How often do you look him in the eye? Are you giving him hugs and having positive interactions?" Wow! I had to realize that I was almost completely ignoring him and not giving him any positive attention. His negative behavior was a cry of his heart...it looked like just bad behavior but it was really his way of saying "Mom, do I matter to you?" Once I realized that, I worked really hard to create positive interactions with him and things got a lot better.
Hope this helps!
God's blessings!