I don't know how a writer can operate without going out as a reporter. Think of the feast that's out there. ~Tom Wolfe
One of my favorite childhood books was Harriet the Spy. In addition to her role as a spy, Harriet was a budding writer, and her trademark spy notebook was the means of capturing not only clues, but writing ideas. Naturally, I got a spy notebook of my own, with Harriet's warning "Do not open on pain of death!" scrawled across the cover. I religiously copied down all sorts of information about my classmates ("Jennifer Hardy has catsup on her mouth already - did she eat hot dogs for breakfast?") and observations about the life ("People are ridiculously mean to one another - why can't we all get along?")
The world is a feast of writing ideas if you train yourself to look for them. Get your own version of a "spy notebook" and carry it with you in purse or pocket. Sit in a coffee shop for an hour on a Saturday morning. Take note of people and allow yourself to wonder about them. The young woman in the corner with her stacks of papers and notes - what is she studying? what does she hope to do with her life? The elderly couple holding hands in a back booth - have they been happily married for 50 years, or is it a new relationship coming to flower unexpectedly at this late stage of life? Surreptitiously eavesdrop on conversations - borrow a snippet and use it as the opening line for a short sketch, poem, or story.
There are thousands of ideas out there for the writer who knows how to pay attention.