Inventing Reality: A Guide to Writing Science Fiction
What is 'it'?
Avoid starting a paragraph - and especially a story - with “It”. As a pronoun, “it” is shorthand for another word that preceded it, such as: “The phone rang. It woke up the baby.” You know that “it” is the phone ringing. If the opening sentence starts with “it”, however, the reader doesn’t know what “it” is.