You’re reading a book. The protagonist is a female, tall, willowy thin, beautiful, kind, caring, compassionate, smart, with a high-paying job she loves, and a loving husband. She is sweet and honest, and never fights with anyone. She doesn’t have an addiction to chocolate, and she never drinks too much wine.
At this point, you’ve probably chucked your book at the wall, right? Here’s the thing about writing fiction. Your character cannot be perfect. No one wants to read about characters that are perfect; they WANT bad thing sot happen to your protagonist. On top of that, your character will be uninteresting, and your conflict will be harder to sustain if you don’t throw in a few flaws. So what do I mean by flaws?
Sure, she can have a crooked nose, or a stutter, but that’s not really what I mean. Your character has to have at least one deep-seated psychological flaw. Something deep, internal, something that will fight against her every step of the way. This is where your back-story will come in handy; you’ll need to figure out what happened to her to make her have that flaw, or it won’t be believable.
What are some of possible flaws? Lack of ability to trust people, fear of new situations, fear of asking people for help, fear of looking stupid, fear of showing who you truly are, fear of relationships, etc. Did you notice all of those flaws are based in fear? Personally, I think that those are the most effective ones. You can always use flaws like being arrogant, or being prejudiced etc, but those flaws can be harder for your reader to accept. No matter what anyone says, EVERYBODY has something they fear. The trick is to mine those fears, exaggerate them, then give them to your character. That’s what will make readers identify with you protagonist and keep turning the pages.