I can’t speak for other authors, mostly because I don’t know any, but the writing process can take an extreme amount of time to do. I just spent ten minutes trying to figure out the best way to say she was in shock without repeating myself (my characters are in shock a lot).
Then there’s all the research that goes into it. Even though you’re writing fiction, you can’t just make stuff up. Well, most of it you can, but it also has to have some degree of accuracy. I do a large portion of my research online and generally prefer two resources from legitimate providers. If I use Wikipedia, which is rare, I check their references for validation.
I try to write about places I’ve been so that I can include some little gem about the location. For example, the novel I’m working on now takes place in San Francisco, a beautiful city that was both fascinating – I can smell the blubbery sea lions on Pier 39 from here, and terrifying – hairpin turns on Lombard Street and me without a barf-bag.
It really is true when they say write what you know. I know hospitals and I have first hand knowledge to the ins and outs of daily routines and the people who work there. Maybe that’s why I don’t like TV shows that take place in a hospital. *grin*
When I first started writing I read everything I could on how to write, and five years later, I’m still reading, but I’ve learned that the most important thing is to write from your heart on what you feel. It resonates with the readers.