In the three sonnets of Amoretti by Spenser what are the specific Petrarchan elements and how does Spenser rework them?

There are 89 sonnets in Spenser's Amoretti sequence - and they are all Shakespearean (not Petrarchan).

The only typically Petrarchan element of the Amoretti is the idealised love-interest - which Petrarch himself inherited from the Troubadour tradition.

Spenser does not make any notable innovation to the concepts of ideal love (Shakespeare would do so, by playing with whether a real of an idealised love was being addressed).

Perhaps you need to rephrase this question.