What is a good way to annotate a poem?

Well annotating poems can actually be simpler if you do it in stages, to begin with a good trick in understanding a poem is always to read it out loud, paying attention to the specific punctuation used, then you can get a sense of how the writer meant it to sound. Then if you go through the poem and make notes on it through how you think it is intended based on how it makes you feel and how it sounds, just note down any of the ideas you have around it and on specific words or lines that you think have a certain impact. Then if you go through the poem again and note down what the writer has done technically, looking for similes, metaphors, rhyming and any other techniques they might have used, it is also always good to note down what person the poem is written in, first, second or third. Then if you go through the poem again looking for any notes that match between how the poem made you feel and what techniques or styles the writer has used. This will give you a good basis for annotation and you will often find you can develop your annotations from what you find in these steps.