Most of us are probably pretty good at planning a plot, to whatever extent we like to plan. It's something we learned to do in school, whether plotting a story for Creative Writing class or outlining a research paper. Even if we don't formally plan our stories we know where we want to go, more or less.
This kind of planning is usually based on plot points, on events, following the path our characters will take. A plot map is our storyboard, a useful tool--many writers will say it's an essential tool--for keeping the story moving and even for fighting writer's block by reminding us of where we need to go next. The quality of the plot aside, a plot plan or story summary is not that difficult to do because it follows the natural development of story that we learned when we were very young: this happens, then this happens, then this happens.
There's another kind of planning, though, that is much less natural, requires more thought, and makes the difference between a readable story and one that sticks with you. In a memorable story, the story events are accompanied by an emotional plot. It's the emotional reactions and effects of a story that make the reader sympathize (or loathe, or whatever) the characters as they move through those story events. It's the emotional content that gives the story meaning. And yet, we don't usually think about the emotional content when we plot out our stories.
Some tools for planning a novel, such as yWriter, help by encouraging the writer to note the characters and conflicts that occur for each scene. These help, but they are still more or less plot based. They don't delve into the emotions of the characters, the reason why the plot twist or the event matters.
Any writer who plans has favorite tools and methods, so I'm not going to try to suggest The One Surefire Way to plan the emotional plot of your story. But I will give one example, a pretty old-school method that we can all understand and adopt to our own preferred tools.
I'm talking about the good old index card.
If you've used index cards (or some computerized alternative) to plot, you know they work pretty well for planning the basic content of your scenes in one or two lines. They can be shuffled and rearranged and played with until you have a structure you like. This works very well. If you use this method, or a similar one, you only have to do one more thing to plot your emotional structure. For each scene (or whatever unit you use per card), turn the card over and note the emotional structure of the scene. This might contain the character's reactions, how it makes them feel, or whatever works for you. Basically, it's the why of the plot, the reason the events on the front side of the card matter, what they mean to the character, and (don't forget this part) the way you hope to make the reader feel.
You don't have to go into great detail about the emotional structure. Make notes for yourself so you remember what you wanted to accomplish with each scene. The front of the card might say something like "Billy finally finds the magical talisman in the undersea city, but the evil seahorsemen get there at about the same time and whisk it away. " The back might say, "After all he's been through, all the danger and disappointment and close calls, to get this close and then lose the talisman is too much for Billy, and he seriously considers giving up. It's not worth the trouble. Why should he care if the island princess gets her trinket? Volunteering for this mission was a bad idea to begin with. Let her find her own dumb talisman."
Whether you use index cards, stickies, a spreadsheet or database, plot software, a mind map, a Word file, or a pile of napkins, you can adapt it to include the emotional content of your story. Doing so reminds you that every scene, every event, every thing that happens, has to have a purpose, and has to affect your characters' emotions in some way. We've all been told by our beta readers or critique group that an event is cool, but they want a reaction. This method helps you remember that reaction, the thing you know the character feels but might not always communicate well. Your readers read your pages, not your mind.
Remember, the plot keeps the story moving, but it's the emotional structure that makes us care. It's the emotional roller coaster ride the character goes through that keeps us involved and that creates the real payoff in the end.