Know what's being asked of you. Read the paper assignment carefully. If the assignment is made orally in class, take notes. Discuss the assignment with class members and with the professor. Clarify for yourself what kind of paper you will be writing. Are you being assigned to interpret? Critique? Discuss? Analyze? Conduct new research? Review? Argue? Note comparisons and contrasts? Each of these assignments differs significantly. Discuss the expectations your professor has when s/he asks you to "analyze" rather than "review." Before you begin to think about topics, understand your assignment.
If you are a graduate student writing a thesis, you will not receive a topic assignment from a professor; you must make that assignment to yourself. Take time to think about what you would like to know and how you could best come to that knowledge. Clarify for yourself what you intend to do by asking the same questions posed above. What is your assignment? You will discuss your options with your major advisor or the chair of your graduate committee.
For undergraduates, selecting your topic will depend on your assignment. If you are going to compare and contrast, you need to select a topic where comparison and contrast will be possible. If you are intending to review--such as review literature for a specific area--you will need to identify some areas of interest and go on an expedition to the library to discover which of those areas provides you with available material to review. If you have been assigned to critique, you will want to select a topic you find intriguing so your critique will engage the reader. In each case, your topic selection needs to be directly related to your goal for writing the paper.
Be careful not to choose a topic that is too broad. One way to narrow your topic is to search communication literature at the library. Expect the search to take several hours. Look for academic journal articles that focus specifically on the topic you have selected. Look at the scope of the topic used by the authors of the article. Is their scope narrower than yours? For example, you might be thinking about writing a paper that reviews all the interpersonal literature about nonverbal communication. If you looked for articles about nonverbal communication in academic journals, you would learn that your search generated hundreds of articles. That result lets you know your topic is too broad.
Once you discover this problem, narrow your topic by increments. You can decide the increments for yourself or you can use the articles you generated to help you. If you rely on your own knowledge, you might ask yourself, "What categories of nonverbal communication do I know about?" You might recall categories like gesture, proxemics, eye contact, and touch.
If you are not sure about what categories exist within the topic of nonverbal communication, you could look at titles and abstracts of twenty or thirty articles that surfaced when you searched for nonverbal communication. In those articles, you may begin to see patterns--ten articles about eye contact, three articles about touch, etc. Select one of the patterns as the next smaller increment you will search.
Using either process, you might decide to narrow the nonverbal topic to eye contact. If you searched the academic literature for eye contact, you would discover you were still generating too much research to review; you would conclude that the topic needed to be narrowed even further. After going through the same process again, you might settle on a review of literature about aversive gaze. You will have narrowed your topic from a broad one of nonverbal interpersonal communication to a narrow one of aversive gaze behavior.
Narrowing a topic can be a difficult process because you want to know it all. You may feel as though you are leaving out something important if you narrow your topic to such a small slice of the information. Your feeling is a reasonable one. Part of the challenge of reading, writing, and conducting research is learning to limit your topic so you can thoroughly and exhaustively examine it. Your goal is to examine this topic in minute detail. To accomplish that goal, you must select a narrow topic rather than a broad and sweeping one. That narrow topic becomes the starting point for your paper, so select a topic that interests you in some important way. Your investment in the topic must carry you through to the completion of the paper.
The other problem you might encounter is that you find no research at all covering your topic. In this case, think of other words you might use to access your topic. For example, if you are looking for conflicts teenagers have with their parents, you might begin by using "teenager" as a key term. If you retrieve no sources, you might use a thesaurus to find other terms to use. Words like "adolescent" or "child" might lead you to appropriate sources. You also might use other avenues into the topic, such as "families" or "high school" or "secondary school." Once you find a source, look in its bibliography for other possible sources. Use words from the titles of these articles or from the texts of these articles as key words to find more sources. This kind of detective work is critical to good research.
When you decide to focus on that single area, you may feel disappointed to leave out all the many other interesting areas you considered. Console yourself by knowing someone else may study those topics or you may study them yourself at another time. Recognize that only by selecting a small area and bypassing all the others can you accomplish the careful and detailed examination that is your goal.