Are you funny? Do your friends laugh a lot when you share little anecdotes? If you're funny by nature, you might really struggle to write a tragedy or dramatic novel. If you're not a touchy-feely affectionate person, maybe romance isn't your genre. You should write in a way that's true to your own nature...because this is how you'll do your best writing.
You've probably heard about authors who need to find their voice, or the ones who already have. Your voice is really just your natural personality, and the way it appears on the page. Certain writers have their own distinct style, a way of writing that evokes certain feelings.
What I'm saying is this: funny people are more likely to write funny. People who are a little more in touch with the dark side may be great at writing horror stories or dramas. And if the past is your passion, consider writing historical novels of some type. Write your books the way you approach your life. Write about what you like, situations that intrigue you, and allow your natural personality to shine through in the narrative.
If you know who you are in life, it's much easier to figure out who you are as a writer. Always write as who you are, and you'll be a better writer.