Hi:
Good point. On both of my novels (one published and one sitting on my publisher's desk) I created the plot ideas in my head and just went to work on them and started writng. HOWEVER, when I got up to the more tricky passages, where characters nd sub-plots needed to converge, I did make an outline as well as a time line for the events and the people in my stories to interact.
Also, pull a lot from your own experiences and even find interesting facts from reseach that can be woven into your story or create a plot twist.
Chris Berman