If you're having trouble getting started writing a Shakespearean sonnet dealing with love, I suggest that you read some of Shakespeare's own sonnets, many of which deal with that subject. Sonnet 18 is a famous one. It begins with
Shall I compare thee to a summer's day?
The next one also deals with love. Sonnet 19 begins with
Devouring Time, blunt thou the lion's paws
Almost all of Shakespeare's sonnets have the same rhyme scheme. It is: abab cdcd efef gg. The rhyming closing couplet is one of the main characteristics of the Shakespearean sonnet.
One of my favorites involving love is Sonnet 71, which begins with
No longer mourn for me when I am dead