I have used these, one per child, as whiteboards in the classroom to improve sentences and produce sentence variety in the children's writing. Once created, I printed and laminated them. I used a basic sentence on the whiteboard and then took the children through possible ways of improving a basic sentence. They could then do this form themselves on the whiteboard.
Once this activity has been done a few times, either as a whole class or in a guided writing session, the children can do this independently without modelling from me. Eventually it lead to them confidently adding these learnt skills into their own writing because they had become habitual.