You'll read the same advice again and again - write a great book - and that's because it's true! But more specifically, write a story you're passionate about. Don't follow trends, and try to put yourself in the mind of a reader. Write the book you've always wanted to read. Think of your favorite books - even if they're in completely different genres - and ponder what makes you like them so much. Incorporate those elements in your story and you'll be surprised at how little genre matters, because the same things work consistently regardless of genre. As a reader, I think every great story I enjoy has love, adventure, a vivid setting, and an epic climax. What do you think every great story has? Don't think about what other people think is great, it's about YOU.