Have your characters got enough to play for? Their ambition has got to be strong enough. It’s no good just wishing for something to happen. Have they the means, or the ability to find the means, to achieve them? What will they do to achieve them? Have they got limits? Can they see to the end of the road? Do they know where they want to end up?
Does your setting have a history, which may well affect your characters? The Fairy Kingdom has a history of wars between witches, wizards and fairies, leading to barren areas, which in turn is leading to overpopulation in certain parts of the realm. This led to Eileen suggesting the more responsible magical beings living, in disguise, on other worlds. She got shouted down yet she knows this issue won’t just go away no matter how much the Queen and Council try to ignore it.
Has your world got issues it needs to face? What is its system of government? If your world seems real to you, it should seem real to your readers. And every world has to be run by someone - someone with a past, character traits that can benefit the realm/cause it great problems. There’s got to be some great stories in that!
Do your characters have depth to them? Do they fall in love, hold grudges, take revenge? Do they develop say from wanting revenge to finding revenge wasn’t as satisfactory as they thought it might be? Can you see why your characters act the way they do?
Do you show why your characters are villainous? Is the reason good enough to keep the villainy going or can it be overcome? Do you show how your world works? What’s the system of government? Are there those who resent the way things are run?
Keep your writing tight. No unnecessary adjectives etc. Can you justify every word you write? Tight writing leads to a good, quick pace and easy reading. Less tight can lead to a more flowing style, which could be appropriate for the pieces in between the moments of high drama. Don’t let such less tight writing go on for too long. You want to use it to serve you, not to unwittingly bring in a “boring” bit (it will seem boring if the slower flow drags on).
Can you picture your characters? I don’t have character biographies, though I can see the point of drawing them up, but I can see the type of being that L’Evallier is for example in my mind’s eye and it makes writing for that character a lot easier.