The introduction of the comparison and contrast paper should cover the main point that you will be discussing. Explain to the audience what you will be comparing and contrasting, and what the purpose of the comparison and contrast is. The introduction should also have a strong thesis statement. The thesis statement should overview the key similarities and the key differences between the two items. It may also explain the significance of the differences and similarities. For example, "Majoring in psychology and sociology both lead to careers that study people and how they think and interact. However, majoring in psychology allows students to help people directly through therapy and counseling services.