Create a hook that introduces the idea in an extraordinary way, perhaps connected to another idea readers wouldn't typically see. As an example, begin a paper about spaying and neutering pets with a hook about a lack of state grants. Begin with basic state monetary struggles and then narrow the topic to overcrowded animal shelters. If readers see that numerous aspects tie into your main focus, it's likely that one aspect applies to their lives. Readers will be personally invested in the article.
Readers enjoy laughing at simple jokes or incongruity. Find a real situation from your research regarding your topic to hook readers with humor. Quote a television show or movie that you can connect to your topic. Personalize the humor and tell a funny anecdote from your life that also provides insight into your passion for the topic. Quote someone famous who has little connection to your topic, but whose quote applies to it.
Writers often use the funnel method when they write an introduction paragraph. This requires starting with a very broad topic and narrowing it to the thesis. This provides an effective hook because readers will question how the generalized and broad beginning statement relates to the paper's actual topic. It also gives a perspective and the writer credibility. For instance, begin a paper about cameras with remarks about cave art; make the reader wonder how caves connect to modern recording devices.
A hook can interestingly pose a situation, problem or series of questions and then leave the reader wondering what will happen. For instance, report a crime scene and the work police do. As the paper continues, tie the hook into other paragraphs. With the example, continue explaining the crime and investigation work from it. With the conclusion, answer the question or present a solution from the hook. In the example, explain how detectives solved the crime. Mention the hook throughout the paper.