Your daughter is about to go through a huge transition. My DD is 12 and in year 7 and is going through similar now. She was OK in year 6 and probably at her loveliest. We have always been close but she is my first and there is an element of fraught in both DH's and my parenting. DH clashes with her a lot because they are quite similar. I am more of good cop but that doesn't help because it sends mixed messages but I can't always go with DH because I can see his approach doesn't help.
She always has been quite highly strung, even as a baby - very unsettled. I think that is just her, not anything she has done but sometimes we have reacted to it in the wrong way and made things worse. I think that perhaps this is the dynamic going on here, too.
Things I would change if your DD were mine are perhaps some of the suggestions above but what works for us the most is me talking to DD when calm and trying not to overreact myself. NOT easy. For example, tonight, she was going off on one because DS was annoying her and she was at the computer. I usually try to get her away from expensive equipment because she tends to break things in anger. In the end, I could see me trying to get the computer off her was counterproductive and, instead, I gave her a stern warning that, if she broke it, she would pay. She knew I would be prepared to follow through because I have done so recently. The upshot was that she calmed down very quickly and came down to apologise, give me a hug and say she still loved me. Unfortunately, had DH been here, there would have been a stand off and the situation would have escalated and she would have got more angry, leading to a not so good an outcome. The problem DH has is that she must do as she is told at all costs and, of course, she just digs her heels in even more. My opinion is you need to let the small things go so that they are more likely to listen when you deal with the big things. Reading this, I can see a bit of DH here but correct me if I'm wrong. It's hard to just go on someone's post.
We do get the refusing to come on trips. I think that's quite normal. I don't know how stubborn your DD is but, normally, we make her come and she snaps out of it (eventually) and ends up having a nice time. I expect this to get more difficult, though. I would definitely not leave her for a whole day at this age. Far too young. I would also let the little things like clothing etc go but I agree with you about not letting her out filthy. I still do DD's hair for her, too, but this is because she asks me to and I figure it won't be forever so go with it.