First read the poem for what it is about, its subject and its theme; then read it to appreciate further the skill and imagination the poet has used in presenting you with this theme. Even if you are not entirely sure that you understand everything in the poem in your first reading, you can be struck by the writer's skill. If we take a very short poem as an example, you can see that it is often the poet's ability to choose one thing out of the mass of small details that brings a poem to life. Other poems can suggest an emotional situation so clearly and with such intensity that you find the words stay in your memory , even if you could not write them down exactly if you were asked.
Longer poems can be more difficult for the reader. Sometimes the language is unfamiliar; sometimes the theme is not clear at first reading. The general rule is to read the poem straight through to the end, even if you are unsure of the meaning of all the words or phrases the first time around. Often the whole poem will clarify the meaning of the early images or lines. Unless you give yourself the opportunity to read the entire poem, you will not have a fair chance to find out what it is saying.
It is possible, of course, for you to pay close attention as you follow the words in a poem, read it carefully straight through to the end, reread it a second tie, and still find its meaning elusive. Then you might find writing a paraphrase of the subject of the poem helps you to understand it as you attempt to put the poem into your own words. Usually the effort of trying to find your own words to express the subject of a poem will help you to understood it. Writing a paraphrase will force you to spend more time focusing on the poem to clarify your thoughts. This is the first step in the process of thinking critically about poetry.
Poems are "meter-making arguments," so they usually represent an idea or develop a series of ideas in a coherent discourse. Poems are also "language charged with meaning to the utmost degree," so you may have to unravel the ideas behind the words as patiently as you would unravel a ball of string after your cat has played with it. When you write a paraphrase of a poem, you take the chance that you might be mistaken about all or part of its meaning. But you also have a method of clarifying the subject that usually brings you closer to the theme or the central idea that you sense behind the poem's words.