I'm a former K/4 teacher, and the issue of writing is one that comes up a lot at this age. I always suggested creating a writing corner at home like this one from when my son was five:

http://teachingmybabytoread.blog.com/2011/02/28/creating-a-writing-corner/

You want to be sure to stock the writing corner with lots of cool supplies including stationary, stamps, and address labels. Creating a personal dictionary can also help:

http://teachingmybabytoread.blog.com/2011/03/02/personal-dictionary/