Never say anything in writing that you wouldn't comfortably say in conversation. Be yourself when you write. If you're not a person who says 'indeed' or 'moreover,' or who calls someone an individual ('he's a fine individual'), please don't write it.
William ZinsserAbraham Lincoln and Winston Churchill rode to glory on the back of the strong declarative sentence.
William ZinsserThere's no subject you don't have permission to write about. Students often avoid subjects close to their heart ... because they assume that their teachers will regard those topics as 'stupid.' No area of life is stupid to someone who takes it seriously. If you follow your affections you will write well and will engage your readers.
William Zinsser