It might be more helpful if you suggested the actual poem that was being sought out. One thing I have always felt in terms of analyzing the summative action in a poem is to identify the literal action that is happening in the poem. Being able to focus on this might be able to give some level of structure ot the explanation of the surface meaning of the poem. For example, in Ozymandias, what is literally happening in the poem? This might involve determining who is speaking, what progression is evident, and how it concludes. In doing this, one might be able to establish a summary of a poem. A part of this would have to be determining the symbolic meaning of the poem. This resolves in the idea of determining what might the poet seek to gain from writing this poem, what message might want to be sent out, and how their own personal beliefs fit into this scheme. Establishing these elements behind surface and symbolic meaning can help form effective summaries of poems.