Start by writing a one sentence summary of your novel, Not a sales pitch, but the essence of what happens in it. This is harder than you first think. Your instincts will be to hold back information as if you are writing a teaser for the book ...... Don't do that, focus on writing a simple sequence of events
Split that card into three parts, beginning, middle and end, You don't need a lot of detail, just try to summarise the way that part of the book will go. Once done you THROW AWAY the original card and stack these three in its place.
Keep taking a card, splitting it and adding detail
Its a great way of breaking your novel up, after a card has been split a few times you find that you're about ready to start writing the scene that the card gives you. The beauty is you only have to focus on that scene, all the planning and structure has been taken care of in the process.