Think of critical theories like a tool kit. Depending on your chosen work of literature and what research question you'd like to explore, some of these theories will be more useful than others. As you develop your interpretation of your chosen work, try out a couple of different "tools" to determine which one offers the best framework for your analysis.
As you explore and apply different critical theories, think about:
NOTE: Although many critical theories might seem like they only work in certain cases (i.e. that Marxism can only work when you're looking at social class or economics in literature), you can create some really interesting interpretations by using unexpected critical theories in your research. For example, using New Historicism to examine science fiction can produce interesting commentary on societal fears.
This is not a comprehensive list of critical theories. For additional theories, see the additional resources at the bottom of the page.