A simple way to remember whether you need to use "it's" (with an apostrophe) or "its" (without an apostrophe).
The Symbiotic Triumvirate of Narrative
There are three main elements in a story: plot, character and world. And consequently there are three related approaches to developing a piece of fiction: Plot-driven, character-driven, and world-driven.
Wanting to write won't get the words down on the page. Writing will.
Jane peered over the top of her coffee cup and said, “These are not hard and fast rules, just guidelines, OK? First, when you switch speakers, you almost always start a new paragraph.”