For your persuasive speech you'll need to use evidence (sources) and good reasons to convince others to agree with your point of view on a particular subject. Specifically you'll need to:
Take a position on a specific topic. Choose a meaningful, appropriate topic.
What interests, activities, and aspects of your life define you outside of school
What problems - physical, emotional, economic, etc - are currently affecting you or those close to you
What do you think are the biggest problems facing our country, or planet, today
Present an argument of one viewpoint or perspective.
Convince others to believe that viewpoint and share your opinion on the topic.