"I don't have anything to write about", "I don't have a story" - sounds familiar? This seems to be a common roadblock between your enthusiasm to teach and your student's willingness to put pencil on paper.
So here's the antidote - we read some of our favourites - "Ralph Tells a Story" and "Patches Lost and Found" to normalise the concept of a writer's block. This was followed by some introspection, on what is important to us. I showed them my 'heart map', making what I am passionate about, visible to my students. Grade 2s then created their own heart maps, shared it in class and glued it right on their folder for writer's workshop.
And the next time the Grade 2 writers were in search of a story, we said "Don't know where to start? Just write from the heart!"
You can order "Ralph Tells a Story" and "Patches Lost and Found" from www.closetfulofbooks.com.
Older students can draw their own heart map. But it is easier for Grade 2s to have a 'heart' drawn for them. You can download the version I have used by clicking here.