They say you should write about what you know or are interested in. I say write about whatever you think makes a good book. Personally, I’m a big fan of action, thrillers and, of course, James Bond. You can see that those types of story have influenced my books and made my stories what they are today.
Of course, you don’t have to follow this advice. If you think your first bestseller should be a romance, write that. If you’re hoping to create a whole new world and pen a fantasy saga set within it, there’s plenty to start with there; before you even get onto the story itself you could write about the history of the world, descriptions of the races living there and any key events that have happened that could influence the way characters interact.
Knowing what to write about comes from within. When you think about writing, what’s the first thing you think of? Which story is fighting the hardest to be put onto paper?