How does one start a persuasive letter addressed to one's parents for a letter-writing assignment for a class?

The standard account of letter-writing theory analyzes the letter into several parts and recommends specific rhetorical strategies to be used in each part. In the salutation, or greeting, you normally, in English, begin with "Dear X" although some use of adjectives or modifiers can be used to express affection (Dearest, My Dear, etc.) The first paragraph of the letter is referred to as the captatio benevolentiae or capturing of good will. This first should be done by ethos, e.g. when writing to parents constructing yourself as dutiful, grateful, and affectionate. Flattery is another common topic used in this section.