One of the most important messages any author can get or share is that you must be able to relate to your work. It HAS to be something you can feel. You wouldn’t want a full time police officer trying to do your taxes would you? No. Well an audience is not going to accept someone whose interest level lies highly in the field of horror fiction trying to write romance either. You have to stick not only with what you know, but what you are comfortable with writing about. If you know horror, write horror. If you know cooking, write a cookbook. If you know history, write some historical piece. It is imperative that you love your work. That is something I can’t express enough. You should be able to wake up in the morning loving what you do and wanting to do it to the best of your ability. It shouldn’t feel like a chore, it should feel like a blessing and a privilege.
That being said, there are still many benefits of stepping slightly outside of your comfort zone and your area of advanced knowledge. Sometimes the slightest adjustment to your work can help you break writer’s block or monotony that you may feel if you let yourself get too immersed in the fine points of your work. This is a trick that not many people are willing to use, but the slightest tweak of your mental prowess in regards to your work can lead to a potential flood of work, and sometimes the floodgates are opened by a small amount of research or questioning.
Basically the love of your work is your best friend. That is something you should never doubt, and something you should strive towards. Do work you love, because if you love it chances are someone else out there will too.