Here are some guidelines to assist you in selecting 'topics for informative speeches.' Recognize your intended readership or audience: Your speech should target a subject that is new to yet vital to your audience. If you do choose a topic that they are already familiar with, make sure to provide new and exciting information. Age and preferences of the audience: When writing an instructive speech, consider your audience's age, expertise level, and preferences in mind. In other words, you may select a speech subject and content that is appropriate for audiences of varying ages. Additionally, the subject and body should provide readers with something fresh to learn.