Structuralism operates from the assumption that meaning is not inherent in any word, sign, type, etc, but rather that meaning is produced by the structure of relationships among terms.
In literary criticism, the focus is on the "grammar of literature," or the set patterns of plot and character that recur across time and genre.
The classic example compares Romeo & Juliet and West Side Story:
(boy +LOVE girl)(boy's group -LOVE girl's group)
Associate the following terms and people with Structuralism:
-Ferdinand de Saussure & Semiotics
-sign, signifier, signified, relative difference
-binary oppositions, spatial metaphors, equations
For more information, I recommend Culler's Literary Theory: A Very Short Introduction.