Ok, I have a problem and need help. Every time I start to write a story, I can tell I'm ruining it, here are the things missing from my current story: One, I don't have very well thought-out characters at all. Two, I don't have very good plans for where my story is going exactly (like what's supposed to happen or what my character's goal is). Three, I don't know yet what the theme to the story is, the only one I can think of now is trusting in God to protect you (even if a horde of dragons is destroying the huge city you live(d) in).
So my question is, have any of you ever started writing and realized you really had nothing to write about except the basic idea (like in my case, the idea is that there's this huge city and it's being pulverized by dragons)? If so, what did you have to develop first: Characters, Setting or Theme? The reason I'm asking this is because I heard on one of the podcasts that a good way to write is "story first" writing instead of characters or plot first writing. But then also I think a good way to start figuring out my characters is to find out where they spend their time, what they do to live, etc. and to do that it'd really help if I figure out their environment first. WHAT DO I DO FIRST!?!?  
 
 *passes out from excruciating headache caused by thinking about this mess* *wakes up and backspaces a bunch of afljkkladkdkk that resulted from head falling on keyboard and presses 'submit'.