Facing any piece of literature that you aren't familiar with, and being expected to analyse is daunting. But if you approach it calmly, I find it is quite doable. It sounds obvious, but first, make sure to read the question. Several times. Go ahead and underline key words that will be relevant in your answer. For example in 'How does the poet convey the idea of identity through setting?', you might underline 'identity' and 'setting'. Not only will this give you a clearer understanding of how to answer it, but to the meaning of the poem as well. Go through the poem, and again, read it several times. Start to underline and annotate phrases and language that link to the theme, as well as looking out for rhyming schemes, alliteration, similes and metaphors. This should aid you in picking out an argument for your answer. It is also vital to consider the form and structure of your unseen poem, as often poets convey hidden emotions through these means. If the poem structure differs in sections, think about what this could mean, and again, how it can relate to the question. When possible, also try to have a historical/cultural/political link, especially when considering a topic like 'identity' in relation to setting. For example, in poems such as 'Dulce et Decorum Est' by Wilfred Owen, the historical war-time link, is very much relevant and vital to its analysis and the topic of national identity.