Imagine that you are someone living in philadelphia in 1730's who is looking for a job. Write a letter to Benjamin Franklin asking him to hire you as an assistant in his printing shop and stressing character taits of yours which you think Frankilin would like to see in someone working for him. Pay special attention to Franklin's thirteen virtues. Refer to at least five virtues in your letter. The letter should be detailed thorough and imaginative. Oraganized and proper letter format.
What an interesting assignment! Well, you would need to consider how much importance Benjamin Franklin puts on appearance vs. reality. Franklin puts a high priority on the appearance of industriousness, ... so much so that the guy actually wasted time by pushing a wheelbarrow full of papers around town so that people would say, "Wow! Look at that young man! He must truly be working hard!"
I would also pay close attention to the line of work you are currently in (in the 1730s) and relate that to Franklin's past. Perhaps you, too, could be trapped making boring candles? Let Franklin see a bit of himself in you.
(Oh it would be SO much more interesting if you could be someone from TODAY writing that letter. I could go to town about the common practice of pretending to be working on the computer while really socializing on Facebook (i.e. the importance of "looking" industrious, while not truly being so.)
It sounds like you have some background on this provided to you. Since you have a list of 13 interests of Franklin, why don't you choose the one that you know most about or that interests you most. Then you will be knowledgeable. Franklin strikes me as the type that like to talk with people intelligently about common interests.
Well, your assignment is pretty clear; if I were doing it I would read up on Ben's biography and try to make myself sound like he would have as a boy. You would want to tell him how industrious you are, how you are prompt and do not like to waste time, how you are a careful person and how you watch your pennies. I would also mention that you had heard he was interesed in science, and that you are also, and you would like to be able to assist him with his scientific experiments during times when you were not working in the print shop (for free, of course).
As far as propwer letter format, that was not quite as formal in Ben's day; putting your home address and the date at the top, a salutation (Dear Mr. Franklin), and a closing would be the general framework you need. Letter writers of his day did enjoy long flowery sentences.