Regular meter and rhyme scheme. All three six line stanzas are with ABABAB rhyme scheme in iambic Terameter. Such regularity draws you into swaying along with the rhytm as you read it. Overall sound of the poem is melodic and mesmerizing.
The title of the poem is an apparently conscious echo of famous Shakespeares sonnet "Shall I compare thee to a summers day"
Byron sets a contrast with Shakespeare, he compares her with the "night", setting contrast in not only the poems subject, but as well with the Shakespear himself.
This kind of gutsy move was entierly in keeping with his general character.
The contrast between night and day, and dark and light is the image that sets up the whole poem.
Byron suggest that it's the harmony of two contrasting opposites, like night and day, dark and light that makes someone, or something beautiful.
The poet never says that he is in love with woman he describes, but he insists that her "love" is "innocent". He describes her personality almost as much as her exterior beauty, by the end of the poem. Her exterior beauty is a reflection of her interior goodness. So there is yet another binary to this poem (the woman inside and outside traits).
One other major symbol, important to note is that the beautiful woman is brunette. In that time conventional English beauties were pale and blonde.
Yet Byron chooses to praise the woman with "rawen" hear and again points out the contrast of dark and light.
Its a poem that talks about something we are all familiar with, guite enjoyable read.