I am reading: How to Write a Novel Using the Snowflake Method by Randy Ingermanson.
This is a revelation to me. I've read writing books before but this one could have been written specially for me. Planning and plotting are my biggest challenges. I write off the top of my head, as they say, and it does work for me. It is true that the whole thing takes on a life of its own - minor characters take on a bigger role, incidents happen and reasons emerge. But, I'm not altogether happy with my method. I know planning would improve my books and my job would be a lot easier. However, planning in a notebook does not work for me. It kills the story stone dead, in fact.
In the snowflake method, you don't plan in the normal sense but you do exercises which reveal your story and your characters and before you start writing you do have - maybe not a road map or a plan - but you have a body of knowledge (even of it's all made up) that informs your writing and definitely makes it stronger.