Debbie mentioned how hard it is to find time to write when you are working full time. The catch-22 is that it is harder to find ideas and create convincing fictional worlds when you are not working.
Michael Connelly writes so authentically about crime because of his time as a reporter, Margaret Drabble reprises her familiarity with archaeology in every novel and where would Dick Francis be without his intimate knowledge of horse racing.
I guess the trick is to have a fascinating career and then retire young and write. I retired young because of fibromyalgia (a cousin to chronic fatigue) and did mine from my career in public relations for a few years. But now I must substitute research for the familiarity I once had with the daily world of work. I have found that most offices will let you hang out if you come with intelligent questions. But there is an artificality to your visit. Every one is on their best behavior while the writer is visiting. So sometimes eavesdropping is better -- just overhearing a conversation in the booth next to yours in a restaurant gives you a peek into a different career.
And the internet often saves the day for me. I'm amazed in Yahoo groups by the kindness of attorneys and police officers in answering my sometimes complicated questions. The bottom line is that accumulating all those layers of details that make a novel convincing is a lot of work. But the payoff is amazing. You've created a world from mere words.
My current heroine is in the gift basket and estate sale business so I've tried on her job amd attended lots of estate sales and made a few baskets as gifts. I'm not proficient in her world but it's been fun.