Jon Towlson writes two posts over at Dark River Press, comparing and constrasting short stories and novels. I've pulled two representative chunks out below, but the articles are more detailed than that, so do check it out. On short stories:
Many short stories fail because they are anecdotal. Even though the idea is bitesize, it does need to be dramatic. The situation itself can be quite mundane but that situation should be important and significant to the character. Strong writing creates empathy between the reader and the character in a short story and this helps to make the situation dramatic to us.
The novel requires structuring into a coherent long form work, and this is one of the most difficult aspects of writing novels – formulating the plot line/s. Specifically, many writers tend to hate working from outlines because they worry that they will lose the spontaneity in their writing. They worry that their work will lack sparkle if it is too pre-planned. This particularly tends to worry writers coming from short story writing who are new to novels.
I've written two novel-length manuscripts in my youth, one of which was even shortlisted for an 'unpublished manuscript' competition run by Random House back in 1998 (we had to dodge Velociraptors as we rushed from shelter to shelter, in those days). They remain unpublished, and as most first-time novel manuscripts, should probably remain so. Nonetheless, it's shown me that I'm much more comfortable with short stories, especially short short stories, and plenty of his examples ring true: I don't enjoy outlining and excuse my lack of effort in this area with the same vague excuses: 'oh, I just miss the spontaneity, you know?'
This is a personal disgrace. I should pull my proverbial finger out of my proverbial rear end and learn this skill. Writing doesn't just happen, you have to work hard at it. So maybe soon I'll throw some novel ideas around in my head and see what sticks.