Our students write best when they are given the opportunity to explore topics and issues that they are familiar with. The website " Response: Celebrating our students good writing" highlights some of the strategies that can be used to ensure students are familiar with the content before attempting to write.
Writing is also about the value of the words we choose. "Thank You Thesaurus ---" explores how this valuable tool can be used to teach good writing. Within the TES website you will find a handy list of discourse markers students need as they craft their arguments. See "Discourse Markers".