If you are searching for a topic, why not take a cue from others? Or if you are not sure how public speaking works, why not watch a few speeches?
My students receive extra credit for evaluating and studying speeches. All students learn from watching others. Here are sources to use for links. See the right hand column of this blog for additional links and ideas.
CSPAN has an archived of video, audio and transcripts of State of the Union Addresses. http://www.c-span.org/Executive/State-of-the-Union.aspx
American Rhetoric This site features text, audio, and video for thousands of speeches given over the last several decades. You can explore the vocal delivery of various speakers by listening to the audio of the speeches provided, and the videotaped speeches give you an opportunity to see many different examples of physical delivery. http://www.americanrhetoric.com/
History Channel Speeches Browse for speeches by topic, or review the entire list of speeches available on the site. What effective delivery strategies do speakers on this site use? http://www.history.com/media.do
Martin Luther King Video Gallery Part of the MLK Online website, this section features videos of Dr. King's speeches. Listen to and watch these speeches to learn how Dr. King used various delivery techniques to motivate his audiences. http://www.mlkonline.net/video.html
PresidentialRhetoric.com Communication professors Martin Medhurst and Paul Stob developed and manage this website that focuses on information and resources related to the study of U.S. presidential rhetoric. The site includes speeches, links to online resources, and an annotated bibliography of scholarship related to presidential rhetoric. http://presidentialrhetoric.com/
Taming Anxiety when Delivering a Speech This site, hosted by the University of Hawai'i Maui Community College Speech Department, provides some useful tips about how to manage your anxiety while you’re delivering your speech. http://www.hawaii.edu/mauispeech/html/speechanxiety.html