Welcome to the forum....we can always use more writers. Personally I think a guide to what you want to write about is what you enjoy reading or viewing. I wouldn't write Westerns or fantasies, for example, because I don't read them. What draws you in a bookstore is what you should write about. And for every type of book, there is an audience so I would worry less about the audience and more about getting started. Some people recommend having a notebook that you jot down little bits of ideas is a good way to start gathering ideas for stories. Keeping a journal gets you in the habit of working regularly. Reading about other writers can be very inspirational. This forum has a monthly challenge, and there is also a challenge that writers are invited to join on the Challenge Forum. Those can be excellent ways to nudge the muse. Getting published is the last step and not the first. Writing regularly is the biggest challenge. The second biggest challenge, which is what killed my creativity, is not letting doubt creep in. Also, don't limit yourself. Some people only want to write poetry or only want to write screenplays. Sometimes a short story writer will have a poem within them; sometimes a nonfiction article writer will burst out with a novel. I doubt if that's any help. I've lost my creativity in writing and in digital art so I'm the last one who should be giving advice. I do know that the longer you go without doing it, the easier it is to make excuses for not starting. I'm an expert at that.