The idea for my first book began with the main character. Her emotions, hurts, and uncertainties hooked me from the beginning. Actually, she was modeled after a friend, who helped me understand how she would respond to different situations then I applied that to my character. My protagonist grew from being mousy and insecure to a young woman who stood up to the evil tormenting her by focusing on her Lord. She realized that her value came from her Lord.
Usually, however, the plot jumps into my head, then I make my characters fit. I want my characters to be interesting, someone my readers will care about, but more importantly someone who is real. Since I am a pantser, my characters take on their own personalities as I write. I enjoy watching them develop and mature as the story unfolds with each tap of my fingers on the keyboard.
In my current book, my main character and I have been at odds with each other. She wants the plot to go her way, but, as I keep telling her, haha, I know how this book has to fit with the second, third, and fourth book. We are still working on that—you know compromising.
It sound strange, talking about a character taking control of the plot, but I believe, at least for me, that writing by the seat of our pants is fun because of all the surprises on the way.