The ups and downs of a plot make the story interesting.
I found the classic Hero's Journey' plot for someone who asked for a plot guide. This is easily adapted to suit our own needs.
I think the main thing with a plot, is not to drag the story, avoid wordiness, keep it moving forward not waffling off with side stories.
Keep the pace up all the way though. Maintain a variable tension, like with music, rise and fall, fast and slow, soft and hard, melody and rhythm.
Have tension in the plot, and if it becomes too tense, lighten it with a feel good moment and some humour, then increase the tension again, building to the climax.
I'm plotting a novel. One of the first things I do is write down all my plot ideas. Then I call up a copy of the Hero's Journey the hero's journey : summary of the steps This page summarizes the...The Hero's Journey