Before reading the literature which is to be critiqued, research biographical information about the author and read and study any previously published works. Every author has his own individual voice and style of writing. To effectively critique a particular piece of literature, you need to recognize the author's strong and weak points as a writer based on prior research. By becoming more familiar with a writer's style, you'll be able to more easily judge the quality of the current literature.
Asking particular questions during the reading of literature is most important. The more you understand about a certain piece of literature, the more you'll be able to properly analyze the work with regard to tone, format and the author's overall message. Furthermore, as the article entitled "Various Types of Literary Analysis" suggests, there are some "movements in literary criticism that propose close reading and textual analysis of the text itself." Possible questions are: Does the piece deal with generalities or specifics? Does it follow a particular school of thought within the topic or story? What conclusions does the piece of literature come to?
Occasionally, a literary critic can become so "busy" critiquing that she forgets to utilize proper grammar or correct spelling. Most writers fully realize that you must write proficiently, but you can never be too careful when it comes to rewrites and revisions. It almost seems presumptuous to critique an author's piece without writing correctly yourself (especially if your review is negative). Proofread your completed draft at least two or three times to ensure the highest quality of critical writing.
When critiquing any literature, it is paramount to be a thoughtful and considerate critic. Your job is to critique the piece of literature based on such things as how well the topic is addressed and if the piece is nicely structured and easy to read. Even if the literature is truly awful in such areas, you should not be overtly rude or demeaning to the literature or its author. Similar to mastering proper grammar, knowing how to "behave" as a writer is an important habit to cultivate. In short, be constructive in your literary criticism, not destructive. Being a respectful and professional critic goes a long way; besides, someday it may be your piece of writing that is critiqued.