Use an asterisk to substitute for letters at the end of a word (e.g., crit* finds critic, criticism, critique, etc.).
Use quotes to search multiple words as a phrase (e.g., "new age" finds these terms in exact order).
Search authors as a subject to eliminate works written by the author instead of about them.
Limit to peer-reviewed (or at least scholarly) articles to find those most desirable for work at the college level. (Peer-review explained: Some journals require articles to be reviewed by other professionals in a particular field before they can be published. These are considered the cream of the crop in scholarly articles.)
Apply/transfer critical analysis when two literary works deal with similar concepts or forms. For example, you cannot find an article about an author's exploration of an idea or concept for a particular work, but find one for another work by that author. You can use this article to point out how the author explores the same theme(s) in the work you are writing about. This is especially helpful for very contemporary works that may not have a lot written about them yet.
Articles in Spanish can be found in Worldcat (first search), MLA Bibliography, and JSTOR. You may need to search all of these resources in order to find enough articles for your paper.