English professor Anette Hyltoft says every story has one of three kinds of struggles: man vs. man, man vs. nature, and man vs. self. Plot progresses through the establishment of these struggles, description of the struggles, the climax (the point at which the protagonist will lose or win the struggle), and finally the resolution or denouement. Your protagonist may have many struggles all wrapped up in one plot, but there needs to be one overarching central struggle onto which the reader can hold.
Every story has at least some combination of these struggles. In man vs. man, your protagonist has a human enemy who wants to steal his true love, his job, his life, or some other thing of value. Sometimes your protagonist doesn't know who his enemy is until later in the novel; sometimes it's his best friend. In man vs. nature, your protagonist must survive "the elements." Perhaps this involves moving from idyll Iowa to noisy New York City, or living among a pack of wolves. Man vs. self often overlays many of these stories, and its depth usually distinguishes literary fiction from other genres. Your protagonist must somehow overcome something within herself--and it doesn't have to be as large as a drug addiction, or as morally obvious as learning to care about others.
As your protagonist faces his or her greatest struggle, there's a goal that must be attained. In man vs. man, your protagonist wants to beat the antagonist to that goal. In man vs. nature, her goal will usually be some variant of survival. In man vs. self, she may not know her personal transcendence is her goal. For example, your character may have some cognizance of her need to overcome her father's tragic suicide, but unless she's incredibly introspective perhaps her more immediate goal is something more concrete, like getting rid of her foster father. It might be only at the climax of the book that she recognizes the need to let go of her original father. Whether your character knows her inner need or not, the reader should know it, and your character should certainly know his or her short-term goal. In fact, screenwriter Syd Field says your character should have a short-term goal in every single scene. Maybe his overarching goal is marrying this lady, and in Chapter 2 his short-term goal is getting her to kiss him.
As you write, think about what each character wants at each moment in time, and you will write with more clarity in a way that draws your reader's interest. Happy writing!