1. Write down what happened. In your current draft, anyway. Simple sentences, scene by scene. Cover everything. Everything important. Hint: if you leave it out of your outline, it’s probably something you should think about cutting, because you couldn’t be arsed to write one goddamn sentence about it.
2. Code them. If you’re using Scrivener or Trello or some other index card maker thing, then mark the scenes somehow to indicate different metrics. I mark plots/subplots and viewpoint character. Then I lay them all out in order and see how they stack up. Does one of the subplots disappear, only to reappear at the end? Or never reappear at all? Am I spending more time inside a secondary character’s head than I am inside the main character’s? Cast the augury of the cards. They will reveal your weakness, through which your enemies may strike at thee.
3. Patch and fill and cut. Move stuff around, change viewpoint characters, create some scenes that resolve that subplot…or cut it altogether. Make it count or flush it.
4. Write down what should have happened. New set of cards, writing down what needs to happen now that you’ve changed fucking everything. This is the worst. It’s okay. We’re almost done.
5. Check yourself before you wreck yourself. Mark up your new cards with pacing elements: action, exposition, character revelation. Does the flow work now that you’ve added in things? If not, get more cards. Oh god, more cards. Keep working at it until it flows like sweet, sweet bourbon. Which reminds me: you might need some bourbon.
6. Mark the scenes as Stop, Go, and Slow The Hell Down. I use the Label function to turn my cards green, red, and yellow. Stop is a new scene entirely. Go is a scene that can be taken 90% verbatim from the old draft. Slow The Hell Down is a scene that needs to be tinkered with in order to fit. Try not to freak out over the amount of red and yellow cards.*
7. Begin. Again. This time with a plan.
*For example, I sat down with a huge coffee at the local caffeine pusher and worked my way through all these bloody cards and here’s my breakdown: 13% Stop, 55% Go, 32% Slow The Hell Down.