Consideration for audience can be a challenge in a composition course; students, I think, tend to see themselves writing for the teacher. That's why (inspired by my brother) I'm now asking students to read their in-class informal writings aloud. It is not that I want to intimidate them (although some are obviously frightened by the prospect), nor that I want them to learn how to read aloud (though they may). It is that I don't want students to think they are only writing for me. Knowing that they may be reading their responses aloud, they may write differently. They may gain a better sense of public identity as a writer. That seems important to how we use language.
I'm hoping students engage more deeply with their writing (particularly tone, style, form) when they are "performing" not exclusively for a teacher, but for each other.