I just finished outlining another book, and have found a few things that have worked for me.
The entire process of meditation and then the actual process of writing the plot points down with a pen and paper took about two weeks. I needed that time to mull over some ideas that I wanted to fit in, organize each of the story threads (central characters, antagonists, secondary characters) and the end up with a complete story. Beginning, middle, and end.
I know that in Scrivener you have the option of outlining your book like a cork board, and I started doing that. The only issue with me is that I am rarely in front of my actual laptop. If I am, it's because I'm at home and I've made the time. The days of my Macbook Pro being conveniently portable are about two years in the past. Now? I simply carry around my iPad and a notebook (that never fails!) and do all my writing and creative thinking with those. Anyway, I ended up resorting to actual physical notecards this time as I did on my first book.
The easiest part of this process was that I could add notecards and swap them around if they didn't make sense. I love starting at the beginning and working my way to the end. There is an undeniable flow that comes from visualizing the story this way. That may be different for you, but for me, I need to see the cause and effect in chronological order. I did know the ending before I started though, so I wasn't blindly wandering in the dark!
Once this outline was finished, I consulted with one of my beta readers to see what she thought about some of my plot ideas. I ended up getting some other story threads that I hope to explore later on.
Certainly, I suggest using the three act structure like the screenwriters use. It helped me get this story down quickly compared to the months of my first outline, and I am now ready to start writing each chapter. What is the life-upside-down event at the beginning? What is the turning point? The reversal? The black moment of no return?
If you're at this stage in your novel-writing, I highly suggest a stack of notecards. You never know what you might add, subtract, or swap around as your story takes root!