Should I think in chapters as I write?
I don't think you should think in terms of chapters when you write a novel. The other thing too, that you should be aware of is that what starts off as chapter one will not necessarily stay as chapter one. The chronology of a novel will change as you are writing the novel. Very often chapter seven becomes chapter three, chapter four becomes chapter one, and you shouldn't worry about that. You have to start a novel somewhere and by the end of the book you'll find that the organization of the chapters might change.