Have you spoken to your DD's school teacher about what story-writing techniques they teach them at school? I remember my DS told me about a 'story mountain' a while ago, which was useful for giving his stories a structure.
Have you tried mind-maps/spider diagrams to organise ideas, or even simple bullet-point planning? It may also help talking to your DD about what she wants to write, and why, before
she starts writing; that might help her think it through properly. What you want her to write is an interesting, nicely flowing story, ideally organised in a few paragraphs, with a clear beginning, middle and end. Maybe you could give her a few examples of what those sections may include.
From what you've said, it sounds as if your DD is trying to think about too many things at once and ends up trying to do too much, resulting in confusion.
With my DS, I would read his story, talk it through with him and ask him to think if there were any changes he wanted to make in terms of the words used, e.g. use a better word, add an adjective or an adverb, or simply things making (or not making) sense. Once we did that, he would write the same story again with the improvements he decided on, but also paying attention to the structure if it wasn't right the first time. Writing stories in draft, talking them through, thinking how he could make them better and then writing them 'in clean' was what helped his creative writing a great deal.
As for a tutor, you could try to find one but it's hard to tell what to look for. The only thing I can think of is recommendations from other parents who say that their DCs' creative writing improved dramatically thanks to a given tutor. But it really is practice that makes a difference. Good luck!