You might like to think about how this poem presents us with the conflict between art, as represented in the tapestry of the Lady of Shallot, and life, which she is of course excluded from and can't even look at without a mirror to mediate what she sees. Clearly, Tennyson is making a very profound comment about the difference between these two states and their relationship to each other. The desire of the Lady of Shallot to sample life itself, even at the expense of losing her life, clearly indicates the limits of art in reflecting life.
I think you should focus on what you think it means. For example, do you consider it an example of the suppression of women? Does the fantasy contribute or take away from the meaning of the story? Is it still relevant today?