Themes: The themes compare in that both narrator’s of these sonnets are relating the difficult trials they face in life and how they perceive them. The themes also compare in that both narrator’s talk of women and how they are part of their respective lives. In Spenser’s Sonnet 29 (Amoretti) seeks the praise of a certain woman. In Shakespeare’s Sonnet 29, he reminisces about a certain woman’s sweet love.

Structure: Both poems are English Sonnets. An English sonnet is also referred to as a Shakespearian Sonnet. The attributes of this type of sonnet are that it is 14 lines long and the rhyme scheme is: ABAB, CDCD, EFEF, GG. There are no breaks for stanzas in this type of sonnet, the lines run without a break. Therefore, the whole poem appears as one large stanza.

Figures of Speech: The similarity in “figures of speech” is that both poets employ heightened speech and English of an older style, with words such as “beweep”, “doth”, “quoth she”, “sith”, and ‘therewith”.

Contrast

Themes: A contrast in themes is that in Shakespeare’s sonnet, the narrator has a very positive view of the woman – it is an elegant end to the poem as he remembers her love and what value it gives to him. In Spenser’s sonnet, there is less of a positive tone in relation to the woman. He calls her stubborn right from the get-go in this sonnet and also says that she scorns him.

She looks upon the victors who are at the bay where she is; these victors have taken over the bay from the vanquished, and they are praised even by poets. The narrator seeks this kind of praise from this stubborn woman – he initially set her up in this bay region. He seeks to perform great feats that would exceed those of these victors so he can earn praise from her.

Therefore, Spenser’s sonnet has a theme of Vindication in regards to the woman. Shakespeare’s sonnet has a theme of Love in regards to the woman.

Structure: There is no contrast in the structure of these two sonnets.

Figures of Speech: The contrast in the “figures of speech’ is that Spenser’s style doesn’t ring with as much clarity as Shakespeare’s. In addition, Shakespeare’s figures of speech move more smoothly from line to line, which in my opinion makes for an easier read.

Sources: Shakespeare Sonnet 29

              Spenser Sonnet 29 (Amoretti)

Are you asking about a particular sonnet of Spenser's or the Spenserian sonnet in general (a style of sonnet)?