According to Colorado State University, topical speeches are those that are structured by topics and subtopics, as opposed to chronology, geography, pros and cons, or any of the other possible speech organization methods. Topical speeches work best for explaining complex, multifaceted issues, as they break the topic down into simple components. Writing a topical speech requires you to pinpoint a clear thesis and outline several supporting categories. The sequence of subtopics should flow logically and build on the previous information to provide a clear explanation of the central topic.

Pick a topic for your speech that is somewhat complex and multifaceted. Don't choose a topic that can be explained briefly such as "The Names of George Foreman's Children" but something broader such as "Family Values According to George Foreman." Choose a topic that isn't very well-known to the audience since you want to spread information not simply reiterate it. However, the topic should still be relevant to the audience enough to hold their interest.

Divide the main topic into several subtopics in order to explain it in a clear, logical manner. For example, if your main topic is "Causes of the First World War," you can split the topic into "British Colonialism," "German Militarism" and "The Assassination of Archduke Frans Ferdinand."

Open by introducing your topic and explaining why it matters to the audience. According to "Public Speaking: Concepts and Skills for a Diverse Society," an introduction should link yourself to the subject as well as draw in the audience. List the major subtopics in the introduction so the audience has a preview of the speech and knows what to look out for.

Organize the subtopics so they flow logically and build upon the previous information. Though the speech is topical, not chronological, it often still makes sense to discuss the subtopics in a progressive order.

Conclude the speech by synthesizing your subtopics into a concise explanation of the main topic. For example, say "Thus, the First World War occurred due to a culmination of rising tension but was set into action by a single gunshot." Explain to the audience why the topic is relevant to them and, if possible, initiate action.