Summarize
Some annotations merely summarize the source. What are the main arguments? What is the point of this book or article? What topics are covered? If someone asked what this article/book is about, what would you say?
Assess
After summarizing a source, you need to evaluate it. Is it a useful source? How does it compare with other sources in your bibliography? Is the information reliable? Is the source objective or biased? What is the goal of this source?
Reflect
Once you've summarized and assessed a source, you need to ask how it fits into your research. Was this source helpful to you? How does it help you shape your argument? How can you use this source in your research project? Has it changed how you think about your topic?
To get a feel for what an annotation looks like and what it includes,
here are some Example Annotated Bibliographies in different citation styles: