So, what am I talking about? Motive and Motivations.
I've noticed a problem with character's motives lately, in my own characters and those of some of my friends. I've seen that some characters are realizing facts about themselves and them setting off on quests for no particular reason other then that's what the outline says they do. I'm not satisfied with this. So what if the girl learns she's adopted? I don't follow the logic between that and setting off on a search for true parentage. Why does she feel the need to leave? Why can't she just stay where she's at? These are questions I want answered.
How do you know when you need motives for the character? Ask yourself this question: If the character doesn't act on this, will the character and everything he holds important, still be okay? If the answer is yes, you need to do some digging and find out what need to change to give the character motivation.
Now, how do you come up with the right motivations? There are a couple of ways. First, put something they love at risk. So that if they don't act, there will be consequences. If you can't do that without utterly changing the plot, back your character into a corner somehow, so that the only choice besides the action is something the character fundamentally doesn't want to do. Give them the choice, slavery, death, or something equally unpleasant, or the action. You can often have your antagonist give this choice. And if all else fails, you could have them kidnapped and forced to do the action.
Just please, for the love of all great books, make is clear why your character is doing something! Otherwise, your characters become tools of the author to tell the story. I, as a reader can tell when and author is forcing their character to do somethings against their nature, and it makes me want to throw their book against the wall. That's not a good thing!
So, maybe you need to do some digging and find out why your character MUST take a certain action. Believe me, your book will be better if you do.