When you select a speech topic, you need to find something that you are passionate about, as well as your audience. The way I landed on the topic for my speech is by examining the class's interests and my interests. This way, it is easier to make your speech entertaining and easier to listen to. You will have your audience's attention.
In order to anticipate for upcoming speech projects, focus on your own interests that could be used, but also take note and pay attention to others' conversations, what others wear, or what others' give speeches about in order to identify their interests. For persuasive speeches, try to find controversial topics among your audiences' circles, and explain each point of view of that topic in your speech.