I've never written any novels or books before, but I have a couple of ideas and I'm planning to. My issue is that I feel like I should improve my short stories before taking a step into something longer. Now, I am already suspicious of this thought-processing style, and will most likely reject it when one of my ideas for novels grows so big, that I won't be able to say no to it. I haven't reached that stage yet, so my questions remain. How do you decide to write a novel? Is it the kind of idea for a story you know right away is reserved for a novel? Or do you start by simply writing a story and then decide whether it will be a short story or a novel?