One of the questions I'm asked most often is, "Where do you get your ideas?" At first it seemed an odd question, because ideas are everywhere. They're floating around, just waiting to be plucked from the air and put to good use. For me the question isn't where do I get my ideas so much as how will I ever have time to use all my ideas? (I won't.)
Read the newspapers. There are always interesting articles and columns there, any one of which could be the basis of an idea. Be observant. Watch the people around you. They're endlessly fascinating. Listen in on their conversations. Yes, that's called eavesdropping, but we're writers--we're forgiven the occasional transgression in the interest of creativity. A snippet of overheard conversation can lead to an idea for a book, or give you those quirky secondary characters you were seeking.
Airports are a particularly interesting place to people-watch. Everyone there is on a mission. They're either going somewhere, coming back, or are there to see someone off or greet them upon their return. Everyone has a story. Let your imagination go wild.
Read the classified ads. There are stories there, too, in very condensed form. I spotted a classified ad once that read, "Free. Refrigerator, fully stocked." I wondered, who gives away a refrigerator full of food? Or was it food? Frankly, if I hauled away a free refrigerator, I'd be pretty nervous about unwrapping that package of meat...
When I'm traveling I like to make note of the names of the towns I pass through. Eden and Hell are just 30 miles apart in Michigan. I wonder if Stephen King knows that. When driving in Nebraska I've noticed a sign for a town called Friend. Sounds like a nice place to visit, right? But I imagine the benign name as bait for unsuspecting travelers who find themselves lured in on a dark and stormy night...
You may have noticed my imagination tends to take a dark turn. Probably comes from growing up on episodes of The Twilight Zone and One Step Beyond.
Ideas, they're everywhere.
"Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world." Albert Einstein