So when A Writer is asked questions by The Public at an event like the Hay Festival (now in progress) one of the questions that they will almost certainly be asked is 'Where do you get your ideas from?' And the fact that it is a frequently asked question doesn't make it easy to answer.
But I'm going to have a bash.
1. Observation.
I recently saw Mike Leigh's Another Year for the first time, and though it was a masterpiece. Themes, cinematography, performances, dialogue, everything. Essentially, like the best of Mike Leigh's work, it is based on observation, by both the director and the actors. Lesley Manville, in particular, was brilliant. She was playing the desperate, chaotic Mary, and made a potentially irritating and depressing character so believable and vulnerable that I was rooting for her, hoping she could conjure some kind of happiness out of her wilful neediness and 'inappropriate' drinking. This is the sort of idea that comes from noticing things, small things, the details of life, and ferreting them away somewhere, and thinking about them. Small things encapsulate larger things, supposed truths of life.
2. The unconscious.
The surrealists were keen on this, of course, and so are many fiction writers. Julia Cameron has written about the importance of keeping a dream diary, writing first thing in the morning and getting down the quickly forgotten details of our dreams. Mary Shelley said she dreamt of Frankenstein after trying to write a ghost story with Shelley and Lord Byron - you can be fairly confident that the conversation and the challenge generated the dream, but the dream was essential, nonetheless.
3. Other stories.
Margaret Atwood says that in writing we are Negotiating with the Dead. One of the paradoxes of originality is that it is not a unique outpouring, or the fruit of solitary genius, but an informed and enriched perspective on common experience. (The writer might work in solitude, but their mind does not operate in solitude. Language itself is a collective summation of agreed communication and patterns of expression.) Originality in science is about the small breakthrough, built on the research of other scientists (whose work is something overlooked). The exact same thing is true of artistic endeavour, which is one of the reasons that creative writing students and anyone who takes their writing seriously should read compulsively and across a wide range of genres. Not only does this increase our fluency and repertoire as writers, it also helps us tap into the traditions and the shared stories that make up the collective unconscious of the Zeitgeist.
4. Your obsessions.
If you had what seemed like a great idea, but find it is beginning to bore you, then the reason could be that it isn't something that you care about enough. In order to generate an idea, you need to find a subject or a theme that will never bore you, because it is one of those niggling things that you cannot escape from. I wrote a novel about Shakespeare's Dark Lady, but it is also about my own experience of trying to be a writer, and my own intense feelings about my children. I can't ever get bored with this. (The fact that I then developed another obsession, with Early Modern London and the lives of the people in it was an added bonus.)
5. Writing itself.
And finally - ideas aren't in there, waiting to be mined like oil reserves. They become what they are in the process of being written down. Writing is not solely a mental activity, which requires the mechanical activity of your hands to become real. It is the combination of the brain and the body - which is one of the reasons that I think it's useful to write with a pen from time to time.