Read your assignment carefully, paying attention to the number of scholarly sources required, page-number requirement and any other stipulations.
Choose a general topic that interests you and that is in keeping with the assignment. You will be spending a great deal of time researching this topic, and it will be much more tolerable if you choose something you are genuinely interested in.
Look at anthropology reference sources that will provide you with background on your topic. This allows you to increase your knowledge and to think about your topic in more depth, helping you develop a more specific research question. Some good places to start are specialized reference books and encyclopedias. You might begin with the sources linked at the end of these steps. You can also ask your librarian for resources that your library subscribes to.
Narrow down your topic to a specific research question. Ask yourself, what exactly do I want to know about this topic? For example, if your topic is religion in indigeneous cultures, are you interested in how cultural relativism affects the understanding of a particular religion? Are you curious about the role of women in religion? Are you interested in writing abiout the role of the group and "survive and thrive" theory? Think carefully about your topic and what specifically you hope to learn in your research.
Begin to write your paper. You will be doing multiple revisions, but with your first draft, your job is to clearly state your own thesis, introduce and summarize the scholarly conversation about that topic, and then to explain your own thesis using evidence you have gathered in your research. Be sure that your paper is in keeping with anthropological language and theory. Don't be afraid to adapt to your new field by embracing the language that other scholars are using to describe people, culture and behavior.
Edit your paper and ask for help. Once you have formulated your thesis and have a draft of your paper that includes everything mentioned in the step above, you will want to clean up your writing. Oftentimes the best way to do this is by asking someone else to read over your paper and discuss it with you; another student or staff from an on-campus writing center will be especially helpful at this stage.