To help you with writing your annotations, here are some guidelines from James L. Harner's On Compiling an Annotated Bibliography*:

• Use either a paraphrase or commentary approach. Paraphrase adopts the point of view of the source. Commentary makes its own judgments about the source, though those judgments should be as objective as possible.
• Decide on how overt you will make your judgment of the source. While it is impossible to be totally objective, you should determine to what extent you want to appear judgmental. Remember that you are annotating the source first and foremost. Your primary task is not evaluation.
• Use historical present tense, active verbs ("asserts," "contends," "demonstrates"), and complete sentences. (Subjectless sentences are permitted, but do not omit words simply to save space.)

*Harner, James L. On Compiling an Annotated Bibliography. 2nd ed. New York: MLA, 2000.