To me the most important thing before you begin a new book is to get to know your characters. I don’t like charts or outlines, but there are other ways to do this. And you can do it as you begin to write those first three or four chapters that will set up your book.
Ask your characters some questions about their lives and see what they answer.
Have them write you a series of letters about things that are going on in their lives. This gets your character into first person in your head, so even if you aren’t writing in first person, you begin to get a feel for how they should sound and how they’ll deal with what you’re about to do to them. What makes them happy, angry, scared, anxious. Do they lose their temper or hold it all in?
As much as you can, add complexity to the characters’ backgrounds. That will then add complexity to their relationship. What are their strengths and weaknesses? How do they see themselves vs. how others see them? What was one defining moment in their lives that shaped them? What stands in their way of allowing themselves to love? Or for that matter, allowing themselves to go after what they really want out of life.
When someone asks you your characters’ goal, don’t say, to make the hero love her. That’s usually a given. Her goal should be what she wants in life, what she wanted long before she met hero or villain, if you wish. Then realize that goal may not be what’s best for her, she may not attain it, but it is what she struggles for so that conflict occurs at every turn.
Why does she want what she wants? This is motivation. What has happened in her life to make her want this all important thing?
Then conflict is what happens to keep her from reaching that goal.
Other things important about your character:
Internalization-No she thought, she felt, she heard, she saw. Beneath the cliff, the surface of the lake appeared still and motionless. The moon rose in a clear sky and painted a shimmering path to her feet. Andrea drew in a breath and wiped an unexpected tear from her cheek. Why did everything remind her of Paul? Maybe she would never recover from losing him.
Stay away from too many her heart thundered, her head pounded, her mouth dried. These are okay like salt on food. But if we can see into the internal thoughts, then we know how she feels.
POV-do you go deep into her mind to write the story?
Five Senses, see, taste, smell, hear, feel and the sixth is emotion. Every scene needs a few of these. A sense of place is so important to each and every scene. If you write it with only dialogue and movement of characters your reader doesn’t feel as if he’s there. But let a breeze blow the curtains, a dog bark in the distance, moonlight shine through the window, the aroma of perking coffee fill the air, and you have a sense of place. Again don’t overdo this. A little is often enough.