Hi,
I always start with a clear idea of where I'm going, whether I'm writing fiction or nonfiction. However, as I write it is often the case that my concept doesn't work. The writing takes over and I let that happen. It's kind of like starting a road trip in New York with a plan to end up in LA. However, the scenery is so interesting that I end up New Orleans, or the Colorado Rockies.

I like the advice that we shouldn't let the process be our enemy, but should sit down and do whatever works for us.