For me a novel starts as an idea. For example, the one I'm playing around with in my head came about when a postcard arrived in the mail with a face of a missing child posted at the bottom.
An idea was born. Now what? I have the first chapter written but not set in stone. The hero and the heroine are introduced. Now, I have to think about the entire story before I can go on. I try to see the main plot points as movie clips. I don't write anything down because if the "movie clips" work, I'll remember it. That's when I start my research. The best part of writing as far as I'm concerned. I know how I want the beginning of the story to be, but if the research falls flat, then I have to rethink a new beginning
I like to have a subject in my story that deals with real life that folks can relate to, and/or that will teach the reader something new. I want my readers to feel the way I did after I read: BLAME IT ON CHOCOLATE by Jennifer Greene. I learned so much about chocolate after reading that book I still remember the author and the title!
So, back to my story. Now that I have this idea, where do I go next? Most of the time, while doing the research about one thing, something else peaks my interest and I think.. Hmmm...I can add that and then it becomes a snowball effect.