Unless your instructor assigns a specific topic, you will need to identify a good one yourself. Keep in mind that you don't need a refined topic at this point - most people start with general ideas that they will develop further. Identifying an appropriate topic can be difficult. Fortunately, there are numerous places to find inspiration.
Some Sources of Ideas for Topics
Assigned readings and class discussions
The major themes and ideas of a class are usually elaborated on through course readings and discussions. Your general focus of research and methods of investigation will usually be related to course work. Topics that interest you will come up during the semester, and they can form the basis of a good topic for research.
Your Interests and Personal Experiences
You can often find unique insights into topics by using what you have learned through personal experience. Furthermore, what you find interesting will often be interesting to others. Remember, however, that you are writing for a scholarly audience, so your personal experiences and insights are rarely sufficient grounds for supporting an argument.
Browsing is the process of quickly scanning a number of resources that are all related to one subject to get a sense of the information in them. A good way to identify major topics and issues in a particular subject is to browse through newspapres, magazines/journals, or reference works that are about that subject.
Explore Your Topic...
Remember that your topic and thesis might change slightly as you gather more information about your subject. Keep checking back with your professor to ensure that you are still within the guidelines of the research project.
Keep Notes on Everything You Find!
Keep your lists of citations and keywords handy at all times in order to refine your topic and thesis.