The first thing I do to motivate my students to write is by using a Writer's Notebook.
The second thing I do is I allow my students personal choice in their writing. Now I know many teachers say they cannot give personal choice because of all the things they need to accomplish, but I find my students accomplish more because they have a choice. I still teach and assign different genres, but when we write persuasive pieces, my students write a persuasive letter about something they care about. When they write a historical fiction story it is about a time period they are interested in writing about.
The third thing I do is I try to give my students an authentic audience. Whenever possible I try to allow my students the chance to share their published pieces with someone; their classmates, another class, or with others who visit the school.
What do you do to motivate your students to write? Head over to Ideas by Jivey to read more great ideas!