You hear "criticism" and you might think it means negative reviews. But actually, literary criticism means the study and interpretation of works of literature, like short stories or novels. "Lit crit" is usually published in academic journals, and is written by scholars of literature - usually professors and other folks with PhDs in the discipline. 

If you are writing a paper for class about a work of literature, it can be helpful to read other people's interpretations. Just keep in mind that you may not find a scholarly article that discusses exactly what you want your paper to be about. But that's OK! The text and your own brain are your two main sources. Spend a lot of time with the text, and do your own analysis. 

It can also be really helpful (if not essential!) to read background information about the setting, time period, events, and other references in the story. If you don't understand something, look it up in the databases below.