There are at least 4 types of annotations and most of the time your instructor asks you to combine some of the types. If you're doing independent research, think about the type(s) that will suit your purpose best.
Here are some questions to ask yourself as you are writing a reflective annotation:
Attribution: W. Todd Kaneko, 2009, The Annotated Bibliography.
You can write annotations with two different sentence structures. For examples, visit the UC Santa Cruz Library website.