My second novel was written with no plan, no plot in mind. Just a setting, a character and a question. I let the character travel through her world to find an answer to the question. After the first draft was done, the question had been answered but it wasn't so important to the story anymore. Other questions, problems appeared, new characters became a focus as well.
My second draft has been trying to explore some of the ideas that developed later in my writing and to work in these new threads from the beginning. I've submitted my rewritten chapters to my writing group over the past year and we've reached Chapter Eight recently. Again, my readers asked new questions, showed interest in minor characters, struggled with aspects of the story. So I've been going back over the first seven chapters to makes sure it flowed and there weren't repeats or continuity errors or just problems.
I've also asked another writer to reread all seven chapters together. The problem with submitting 1,500 words at a time to the group that there is often long gaps between sections, as in the summer when I went on holiday, and not everyone can attend every weeks, so readers miss out on parts. Having a reader go over everything up to a certain point can give you good feedback on flow, pacing and development.
I'm doing the same for another writer as he has also submitted about four chapters of his novel and we've both had the same sort of feedback about slow development. Our group mostly contains fantasy, science fiction genre pieces, so our two novels which are literary fiction, mostly relying on character development for their action rather than fighting or physical activities often feel slow. It's been helpful to get feedback on how things are working so far.
And now that I have his comments I'm going over the chapters again. I'm also pushing forward with the next section for group this week. Until I get a firmer handle on the story, I'll continue to go back and rework as I move forward. It would have been easier to have a strong plot sorted before I started, but I can't always work that way. For me fiction develops from a grain of an idea and grows, expands as you learn more about the characters and the place you've set them in. It's one of my favourite things about the genre. I'm willing to take the time to move slowly back and forth over my story until I feel it's ready to face the world.