How do I analyse an unseen poem?

There are lots of techniques to look out for when analysing an unseen poem and this can appear to be quite daunting. However, the best way to start is at the very beginning. Firstly, what does the title tell you? Does it suggest or give clues as to what the poem is about? This should give you a greater understanding of what you're about to read. Secondly the next best thing to do is to have a look for any imagery (metaphors, similes etc.). Thirdly, form and structure play a big part in how a poem is read. Is there a rhyming scheme, is there enjambment and what are the line lengths?
Once you have identified these techniques you can start analysing them and see how they add to the tone and meaning of the poem. Look for any key themes and how the poetic techniques and form relate to these. Also, remember one you've recognized the poetic techniques, themes and tone, think about how the poem make you feel. Poem are ultimately about evoking emotion in the reader and the more you engage with it and allow yourself an emotion response to the words the more you will be able to understand the poem in all its details.