One of the hardest thing for me sometimes in a contemporary is deciding what in the world my characters should do for a living. Sometimes it's so much a part of their character that it's no decision at all--but other times . . . I find myself watching TV just to remember what jobs people have, LOL.
In one of my humorous contemporaries, the heroine is an advice columnist, which is where the inspiration for the book came from. The hero is an insurance agent. I don't know that I've read a book with an insurance agent hero, but I worked in an insurance office for three years, so I knew how funny one could actually be. And it was a blast to have him react to everything in terms of deductibles and claims and underwriting. Trust me--it's how you start to think, LOL. I wasn't an agent, but even I started viewing life through that lens after a while. Like, I see a fabulous necklace on someone and think, "I sure hope they have an Inland Marine policy on that--it's too much to be covered under Homeowners . . ."
In my more suspenseful contemp, the hero is by necessity an ex-SEAL. Again, it's where the inspiration came from. But the heroine is from a culture where women were wives and mothers and nothing more. All well and good until she arrives on U.S. soil, sees women moving about with their male counterparts in the working world, and has this moment of, "I'm not suited for this world. I can't drive, I've never used a computer, I have no skills. Now what?" She'll find her place, of course, but it's a driving force of the book.
There's a big difference to me when reading between a character who must have whatever profession they do and one who happens to. Even when I have to take some time to figure out what a character ought to do, I want to make it so organic to who they are--or even make the not-knowing so integral a part--that you don't put down the book and forget what so-and-so did for a living.