It's complicated... Those that know me, also know that I don't have a 9 to 5 job. One can argue that I have a 24x7x365 job.
The first draft was probably the most challenging time. Because you want to write, and write fast. The ideas are pouring out, the characters want to breathe and you want them to break through. You don't want to let anything derail you. The story wanted to be written and my life tried to be an obstacle. But thankfully, I have a support structure that helped grease the way.
My wife wakes up at 5 AM, I try my best to be up by 5:30 AM. Get ready, check emails from my European colleagues, get the kids ready ("Come on buddy, you have to brush your teeth!"), take them to school ("Okay last hug, I really have to go") and off to work I go. I typically eat in my office... no time to waste. I try to get home before 6 pm to help with the kids (homework, bathe, cook, rescue my wife). By the time we're done, it's hitting 8 pm. I power up my laptop and clear out my emails for the day (I want to face each morning with a clean desk). Between 9 pm and 10 pm I am close to being done with my work-work.
I push the laptop to the side and turn to my desktop. I then put on my headphones, turn on noise canceling and start entering the world I've created in my mind's eye. I go on, until my eyes tear and my head drops every other second. That's usually midnight...
It's not easy. But I have my wife's support. And on an occasional saturday or sunday, she would take the boys out with our friends so that I have a complete day to write. Those were the days that I achieved milestones. A plot element that was troublesome, a character that didn't behave like he should have, or a scene that didn't seem to transport the reader there.
With all acts of creation, you can not do it alone. I know I haven't.