MTM Writing Clinic
An introduction is designed to isolate a specific question or issue, and explain why it matters. Introductions are often difficult to formalize at the beginning of a writing project because it is easier to place your particular analysis in the wider context of research after you've finished developing your body paragraphs. Introductions also need to resonate with the conclusion, so writing these two paragraphs at the end of a writing project can help ensure the unification of your paper.
However, introductions have different goals than your conclusion. You need to place your question or issue in context. It is often helpful to consider the introduction a funnel, with a wide base of common interest or information about a particular topic and ending with the specific point of interest that you will be discussing in your paper. Providing your reader with representative evidence of something you found interesting in your analysis is a good way to make sure the reader knows what you found interesting and why you are pursuing your inquiry.
Many disciplines have specific requirements regarding the content required to be in the introduction. For more information, see Formats Across the Curriculum.