I wish I could remember where I read a piece of advice that I took to heart years ago and give credit back to where it is due. I have clung to that simple, but sound advice, in more than one way. The advice is: Write what you know. In my humble opinion, it is not suggesting you shackle your imagination, or draw a bold line with black permanent marker in which you are forbidden to cross. Rather, I perceive it in two distinctively different ways.
First, draw from your strengths. Without argument, our writing will be more honest and authentic when it resides within the margins of our expertise and proficiencies. It is difficult to describe, with absolute conviction, an event or scenario of which we have no knowledge of. When the readers mind presses the text like a potter presses clay, if the compositions within are faulty, the piece, no matter how beautifully imagined, will never develop into a work of art.
Second, accumulate experiences. Through accumulation of personal experiences, we not only expand the width of our knowledge in which we can write about, but we enable ourselves to create rich, validated portrayals. Yet, experiences are more than familiarities. They are encounters with life. They are inspirations of the soul. Face the world. Face your fears. Face the edge of that comfort bubble. Experience your life, not your limitations.
As you can see, I have taken the advice, write what you know, and have used it as a spotlight, shining into the corners of my writing that need a little more illumination. It also points me, in confidence, to where I've been and brightens the pathways where I'm going. I hope this advice encourages you as much as it has encouraged me.