For many students, choosing a topic is one of the hardest things to do in this class. Start with your interests. What do you like to do? What do you do well? Essentially you are teaching your fellow classmates about your topic. If it is something unique or new to them---that will usually catch their interest.
Once you have some potential topics you will want to ask yourself some questions about each topic in order to find the best one for you.
Research Tip: Before you commit to a topic, choose at least three that you have interest in and do a little pre-searching with some library resources and choose the topic that you find enough research information for.