Among lots of other things, Franklin was a printer. That means he owned a printing press and publish newspapers and other things. He also printed stuff for other people. Franklin also held the job of postmaster. This was a paying job. He saw all sorts of things passing through British North America. He also had a ready system for sending out his various publications including his "Poor Richard's Almanack" which was extremely popular. He was also a well-known scientist. He shared his scientific work with other British scientists and became somewhat of an international celebrity in Europe. Take these ideas and others you may have and provide a bit more ( or a lot) details and you should be able to hit your word quota easily.
Franklin's use of humor and his attempts to poke fun at himself to not seem arrogant. Moreover, Franklin's style is terse and witty; he usually makes his points using as few words as possible. Franklin's style is predominantly didactic as the Autobiography is intended to be read partly as a self- help manual. Franklin contributed to the development of journalism as a type of writing that presents the facts in the order of most important to least important, using as few words as are necessary.
