The reciprocal nature of the skills and knowledge of reading and writing is not something that children are naturally aware of.
I have been demonstrating to my students how they can transfer their knowledge and understanding from their reading to their writing and vice versa. During guided reading or reading to we might notice the same ending i.e. the -er ending and discuss the sound made by these two letters. Then during writing one prompts a child that the end sound they are looking for is the same as the word we looked at in reading.
Another prompt is to look for chunks they know - You know "look" so you will also know how to write "took". The children are encouraged to "stretch out" sounds and this phonic skill or phonemic awareness develops as children begin to write and read more new words.
I have been consciously selecting a range of texts to read to the children to provide models for "interesting" words or rhyming words, structure and grammar in writing as well as widening students ideas and knowledge to write about. I also comment on connections between books to get children thinking about themes or content and have had one or two children now picking up on this and making comments such as this is like such and such a book and giving a reason. When a child might be stuck for writing ideas one can refer back to a book they have read and prompt about what happened then.
Some of my students are very excited to 'discover' that these two subjects are so intertwined and are beginning to prompt each other as to the connections. It is exciting showing and discussing connections and then hearing them being used by the children in their learning.