Here are some guides that will help you get started.
Writing About Literature
Edgar V. Roberts
D.H. Hill Reference Collection PE1479 .C7 R59 2003 (Learning Commons)
This book gives guidance to students writing about literary subjects such as character, setting, and symbolism. It provides sample papers, and shows the steps for writing good literary essays.
Purdue University Online Writing Lab
The Purdue writing program has produced a great deal of information to help students get started writing good papers:
Writing the Literary Analysis (Slide show)