Both of these authors treat writing as their full-jobs--an occupation.
Catriona has a goal of so many words a day--though admitted sometimes she doesn't quite get there.
Simon works 9 to 5 or 6 on his writing.
Both authors do a lot of research. Catriona admitted to writing about a place that was no longer existed, but she learned a lot about what it was like and used it all in her latest book.
Simon likes to go to the places at the time of day or night that he's writing about. He also likes to intereveiw people, people with the ssame kind of problems his characters have or professionals who understand the problems.
One thing he cautioned about was that every police department is different, so if you're writing about a real police department, you better find out what they do and don't do, have or not have.