Telling a writer to relax is like telling a man to relax while being prodded for a possible hernia.
William ZinsserThe most important sentence in any article is the first one. If it doesn't induce the reader to proceed to the second sentence, your article is dead. And if the second sentence doesn't induce him to continue to the third sentence, it's equally dead.
William ZinsserMy commodity as a writer, whatever I'm writing about, is me. And your commodity is you. Don't alter your voice to fit the subject. Develop one voice that readers will recognize when they hear it on the page, a voice that's enjoyable not only in its musical line but in its avoidance of sounds that would cheapen its tone: breeziness and condescension and clichรฉs.
William Zinsser