I often suggest, for children who are 'reluctant' writers, that if you have a tape recorder, or a phone that they can use to record, that they DICTATE their story or essay. They can then listen to it back, amend things if they wish, and eventually write or type it on a computer.
For many children, the ideas are there, but it is the physical chore of handwriting that they struggle with.
Is DD older? The more she can read various sorts of text, and in addition to reading, to THINK about how sentences are put together, and how different uses of text are shaped in different ways.
Thus, a fairy story, or a story about a prince and princess, will have descriptions of the settings, the characters, maybe even the weather. But a recount about going to the seaside, or a description of how to make a cake, will use language in different ways.
And if they need help with spelling, this is a useful book that is easy to use:
An inexpensive and easy to use book, that can encourage children with reading, spelling and writing, and really help them to understand Phonics, is reviewed in the MN Book Reviews section. Just search ‘Phonics’.