I mentioned in the previous post a great little book called "Notes on Directing," by Frank Hauser and Russell Reich. It's aimed at people who want to direct theater, but I think it has valuable content for writers, too. Here's another insight you might find helpful when you are creating a story:
"Realize that the human experience is one of suffering and the resolution of suffering. Legitimate questions to ask of any script: How are these characters suffering? What are they doing to resolve their suffering?"
Of course "suffering" can be of any quality, from fearing for their lives to worried that they will not win over the person they desire, to anxious about passing some kind of test.
Often we talk about what a character wants or needs, which is a good way to think about a plot but it's important to be aware that often what they want is driven by fear or anxiety.
Even if somebody wants something mundane--let's say a middle-age man wants a new sports car--there may be some kind of fear or suffering behind that desire. It may be the fear of growing old, or the fear that he's not attractive enough so he needs to attract women with fancy possessions.
I find it helpful to think about my characters this way because it unlocks a lot of other thoughts that help flesh them out. For instance, at the moment I'm writing a thriller TV movie in which the protagonist's fear is that she will never be as capable as her older sister, who was kind of a parental figure to her. In the course of the story the tables are turned and she is the one who has to save her sister.
Knowing that her feeling of inferiority is a central issue forces me to think about why she is that way--what happened in the past? How else does this influence her in other parts of her life (for instance, her relationship with men)? The answers to those questions end up affecting the rest of the story elements in larger and smaller ways.
(Additional helpful information about writing scripts and books is in my book, "Your Writing Coach," published by Nicholas Brealey and the associated site, www.yourwritingcoach.com)