Every story is about emotional change based on your story’s theme. The hero starts out in a dead-end life and by the end, changes into a better person. Basically the whole story then is a tug of war between forces pulling the hero in both directions.
For example in “Terminator 2,” the theme is that killing is wrong. So in the beginning, the hero (the good Terminator) believes that killing is acceptable to achieve your goals. By the end, the hero realizes that killing is wrong because life is precious.
Therefore the tug of war that the hero faces is constantly having to choose between killing or not killing.
In an early scene, the hero almost kills some young men who happen to see John Connor and the hero in the street. After John Connor orders the hero not to kill, then the hero must constantly be tempted to kill or refrain from doing so.
When the hero breaks into the asylum to rescue Sarah Connor, he simply shoots the guard in the leg so he’ll live. Later when Sarah Connor is about to kill the inventor of SkyNet, the hero and John Connor stop her, although the temptation is to take the easy way out and kill him.
When trapped at SkyNet’s headquarters and surrounded by police, the hero once again is tempted to take the easy way out and kill all the police. Instead, he scares them away or wounds them so they’ll live.
The tug of war is basically temptation like in those old Saturday morning cartoons where a devil and an angel sit on a character’s shoulders, urging him or her to do one thing or another.
In “Legally Blonde,” the hero starts out thinking she needs a man to define her identity but at the end she realizes she can be a strong woman with her own identity. Thus in the middle, the hero constantly wonders whether she’s strong enough to stay in law school or just give up. Then when she’s working on a court case, she wonders if she should just leave rather than stand up for herself and deal with her sexist professor.
Think of your theme and the bulk of your story should pull the hero in one direction or another. This constant struggle creates suspense as we wait to see which choice the hero will finally choose in the end.
Think of every tory as a tug of war between keeping the hero stuck in a dead end life or growing and becoming a better person.