A pretty talented young writer named Stephen King wrote a story entitled IT. This has nothing to do with that story.
This has to do with the overuse of the word it. The word is small, only two letters, yet the impact made by these two letters can drive some people to contemplate -- literacide.
I'm not suggesting elimination. I'd be at an utter loss with the use of it, however, after you've written your preliminary draft, edit your work, putting in the time to search for alternatives.
When you spot the little devil, ask yourself what is the it? Are you referring to a person? Item? By putting in a specific descriptive word, will you be creating a redundancy of phrases? If so, then you need to work a bit harder to be clear.
Writing for others to read requires the author to be knowledgeable about the language while still entertaining. Do the work. Your good novel will become a great novel.
Mistress of the Red Ink Pen