One of the first and most important things that a writer has to do is to decide what to write. I believe sometimes you just know. Its the stories in your head and all that's required is putting them to paper(or computer screen). But sometimes there are so many stories that unless you want half a dozen unfinished manuscripts laying around, you have to focus on just one...or two.
I don't believe that old saying 'write what you know'. I know a lot about Christianity in the Midwest and the South. That's the last thing I want to write about(insert bored yawn here). I believe you should write what you LOVE. What interests you the most? What do you like to read? That's the genre that you are going to be the most familiar with and the most knowledgeable about.
Once you have that settled, then you can throw in what you know.
I love the paranormal. I have all of my life since I was five years old and my brother let me watch 'Carrie' when he was babysitting me. I was hooked. My particular passion is vampires. I know...I know..its been done to death. That's ok because I don't think I will ever write about them. I am so obsessed and so widely read on the subject that I cannot for the life of me imagine that I could do better or think of an original idea regarding them. Now werewolves...thats a whole different story.
I also love Middle Grade. Without an ounce of supernatural element at all. Because that age range is so naturally funny and magical that it doesn't really need it. It's what I know best and I have a secret research weapon too. My son.
So, the genres that I prefer to write in were decided without much anxiety or second guessing. The stories seemed to choose me. What were the stories that chose you?