Writing about poetry, at least for me, has always been an easy thing to do. I may not be going about it exactly as others do but I feel that my strategy for writing about poetry was definitely good enough to get me an A+ from a teacher who said she would not give any A's at all. I choose different aspects of the poem and dedicate paragraphs to them. I organize them into separate paragraphs and they usually consist of:
-Style, what makes it unique, or what stands out, and why
-Interpretation of content
-Feeling the reader gets when reading
-Possible relevance to poet's life
-Relation to time/society
-Favorite quotes, explanations/elaborations
Mary Oliver's A Poetry Handbook is a good source for information on writing about poetry.