L is for Love.
Personally, I think writing what you know isn’t always very good advice. I strongly believe that every writer should write the kind of story that they are passionate about. If you don’t love what you are writing about it will show in your work and the reader will be disenchanted by it.
Writing about something that bores you only make it harder for you to write and complete the work. Always write something you feel strongly about and you will connect with your reader.