OWL (Purdue University, another excellent resource for writing and grammar). This site also includes "Writing about Poetry" and "Close Reading: Poetry," which may be of use for this course.
"The Close Reading of Poetry" by G. Kim Blank and Magdelena Kay (University of Victoria).
"Politics and the English Language" by George Orwell–one of the best arguments against inefficiency and cliché in writing of any kind (worth reading alongside Pound's principles of Imagist poetry and Hemingway's principles of good prose). Essential reading for the student of literature.