In entering any conversation, we must first listen, then speak. Some don't listen, are overconfident of their own insights, and thus fail to really communicate. Others never open their mouths. Pay careful attention to the literary works we are studying. Listen thoughtfully to the comments of other critics, then, like the noble Bereans, search the Scriptures to see if these things are so.
Books are out there that discuss writing about literature.
About Literature is an old standby. If you are interested and can get to a pretty good library, see what they have. If you are really interested, there is still a further dimension closely related to literary criticism, but somewhat distinct, and that is literary scholarship . The critic's main interest is discussing the meaning of a given work, interpreting it. The scholar's is more factual.