Oh What Freedom this!!!

It's been a long long time. I have to come to office early to do this. :)
What shall I write about today? Theres everything and nothing. I've been thinking about the process of novel writing. How do authors construct a story, fit charachters into it and govern everything about them? Its a feeling of immense power but incredibly difficult. How do they ever decide that this is the way the story is goins to happen, this is the way this charachter is going to behave and this is the way I am going to write it. I for one cant even think of a story I want to write about.