Annotation is often the first step in close reading analysis. When you annotate, you identify aspects of language (what you notice) that help you draw conclusions about meaning (why it matters). Writers don't just use literary devices for fun; they use them to convey meaning.
The video overview below will walk you through the annotation process.
On the annotation below, each circled phrase has an arrow pointing to a note identifying what I noticed in the language. Most of these are devices (repetition, personification, contrast). From there, another arrow points to the significance.
The significance statements all help answer the central question. If there isn't a specific question you're annotating for, your significance notes should be about the overall meaning of the passage.