I'm not published, so I'm probably a bad example to follow. I'm writing my first book, and I didn't even write out an outline before starting. I had a vague idea of some plot points I wanted to hit, and just started writing. almost everything I've written has evolved naturally as I've written. I later tried to write an outline for future plot points to include, but didn't keep up with it.
my characters have all formed out of necessity. I need someone to teach, harass, support, or tickle the main character, and then they appear. I had an idea for the bad guys, and they ended up being the goods guys. I developed another lead bad guy, and killed him in the first act, as my story changed.
my story might be crap, and I've got a ton of editing to do. since people changed as I developed them, I have to go back and change some of their dialog or descriptions. I have to add scenes that develop who they are, rather than having already has that in mind because they were last minute ideas.
I recommend starting with a short story or novella, to help you flesh out your process. it's going to take me almost as long to edit the second draft as it took me to write the first, and I'm not even done yet.