One question that always comes up when I attend conferences or do workshops is the one about "trends in publishing." Authors so want to know what the current new trend is because that is what they think they will start writing next. We always answer the same way, we don't know and cannot predict the future. But then we also push that we want writers to work on the novel that is truly going to be their best work. Unfortunately, this message always falls on deaf ears.
Writers are always jumping into a genre because they seem to think that is the best way to get into the publishing business. The problem is that they often do not know or understand that genre enough to write that quality book.
So the big question is, what should you be writing?
I always say to go to your book shelf. What do you read on a regular basis? If you went to a book store, what shelf do you always go to first? Authors who tell me that they read everything really do not. They have their "go-to" genres, authors and yes, even publishers. It is those genres that you should probably look to as the genre to be writing. The simple fact is that you know that voice and understand that voice. Those nuances of that genre are things you get. This means that when you are writing, those nuances will naturally flow from your brain and on to the page.
The other thing to note here is that if you read these books and you devour all of the latest books in that genre, you will see the trends, but you will also know that those books ARE selling. If you are writing in a genre or on a topic that you just do not see out there, then catch a clue, it means people are not buying that topic, at least right now.
I would also add that picking a topic of an area that you work in will also add a lot to the book you should be writing. Why? You understand how that profession works. You get the lingo and you know the environment.
If you truly want to be successful in this business, you have to stick to what you know. I would also add, that it will make your life a lot easier as well!