Writing a preface for an academic project serves the purpose of providing information about (1) the author(s) and their research methods; (2) the particulars about the essay, including, among others, topic, organization, audience and weaknesses; and (3) to whom the author(s) gives the acknowledgment of thanks.
Author and Research
You will want to open your preface by describing your academic background, your preparation to address the topic, e.g., two semesters of independent study in the topic, say, green roofs, and your academic goals. In keeping with your academic qualifications to address your topic, you will also provide details on your choice of topic: Why this topic? What other topics did you consider but discard in favor of this one? What is the draw on you of this topic?
The next point to address is your research. For example, the following questions might be applicable to your explanation of your research methods. What were your sources of research, especially noting primary and secondary sources? What was your method of research? Did you interview subjects? Did you research historical newspapers and other documents? Did you read extensively in the corpus of academic literature in the field? Did you read a collection of contemporary case or research studies? Provide any relevant information that will help to elucidate your approach to research and your research methods. [Prefaces are brief sections of your project presentation, so the questions above are intended to guide your writing rather than serve as a rule to follow.]
Particulars of the Essay
You will want to be quite clear in presenting the topic of your project. You will want to clearly focus your perspective by stating what your project is about and contrasting to what it is not about, e.g., my topic is about the benefit and design of green roofs but it does not cover drainage and structural support for green roofs. One important element to include is the organization of the project. [There are published academic papers available online that might serve as useful examples of how other academicians explain their project or essay organization.]
You will also want to address the audience you have in mind, e.g., owners of corporate buildings who want green roofs rather than owners of private residences who want them. It is important to include mention of what will be gained by the reader from your project (or essay). In conjunction with what will be gained and with the project organization, mention both the conclusions drawn from your project and the weaknesses of your project. For example, continuing our green roof illustration, there may have been no corporate green roofs in your area, so your conclusions are limited and weakened by your lack of first-hand experience.
You will close your preface with acknowledgment of and thanks to anyone who has guided and helped your work on your project.