Research the political history, social norms of the day and the meanings of the archaic language used by William Shakespeare, and other major poets of the period including Edmund Spenser, Sir Philip Sidney, John Donne and Ben Jonson. The key to understanding Elizabethan poetry is to understand their world and "mentally live there."
Take each line of the poem and look at that line individually. First, identify all the word meanings, then phrases that are not clear. When the first stanza or paragraph has a concrete idea, make a note of it along with any questions.
Continue through the entire poem in this manner. Write a summary of both the notations and questions then carefully re-read the poem. Set the poem aside for at least 24 hours or overnight.
Read the poem again, making a note of lines that remain unclear. At this point, few questions should remain. Set the poem aside for at least 24 hours or overnight.
Concentrate on the lines that are remaining by beginning research anew. This technique usually finds answers to the stubborn questions and can break the cycle of remaining stymied.
Consult a literary criticism, which may interpret the poem to an understanding.