Answer:
Read the starting paragraph, or the ending paragraph
Step-by-step explanation:
From my own opinion, altough a poem's main idea can only be understood after reading the entire poem and knowing what the poet is trying to convey to his audience... Readers can also read the starting or the concluding paragraph so that they'll be able to interpret the basic idea of what the poet is trying to tell the readers, and also understand the overall main topic/idea the poet focuses on