All communication has to be clear, you have to know what you want to say and the best way to say it.
One way to start the creative process is to have a private journal and just write. I did this when I was a child. I even believed in Time Travel. On one page of my journal, I left a blank page for my future self to write an entry. Of course my younger self would never see the entry, and I have left the page blank. I still have the journal, it is amazing that it actually made the trip to Israel!
You can have your students write a journal and you can give credit to them if they write a certain amount of text each week. You don't have to correct for spelling and grammar, but for content.
One caveat, when you want to promote good writing, I always use a different color pen, say green. When a student sees a page of their writing covered in red ink, it gives a message that they are sub-standard. So by using green, and only underlining the grammar and spelling problems, it gives a more understanding outlook, that you believe in the student and want to help improve the writing skills. It might be better to correct the errors on another page, or on the back of the page that the student wrote. It will take more time, but in the end, the student will feel more motivation to write more and improve.
I collect the errors, and use them to teach the whole class the next time I teach writing. I never say who made the error, but usually more than one student made the same error and I need to re-teach.
Thank you to everyone who commented about this post.