To determine the rhyme scheme of a poem, label the first line a, then label as a every other line that ends with the same sound. The next sound is b, and so on. Thus
Mary had a little lamb. a
Its fleece was whte as snow. b
And everywhere that Mary went, c
The lamb was sure to go. b
Now you can do the same for “A Widow Bird.” However, be aware that there are such things as approximate rhyme and eye rhyme. In the former, two words ALMOST rhyme, and in the latter, two words are spelled so that one might expect them to rhyme, but they don’t. “Boot” and “foot” are examples of eye rhyme. If you see examples of either in the poem, you should mention that fact in your essay.
Don’t look too hard for figures of speech in that poem. But think about the imagery–the way Shelley uses words to create sensory impressions. What does he make you see, feel and hear? What’s the overall impression that the poem creates?
If you need more help, ask again, but no one should fully analyze the poem for you. If you think hard about the preceding paragraphs (especially two hints in them), you can probably put together a pretty good analysis on your own.