When you are promoting you book do not forget to give free copies of your work to the local public libraries. This is especially true if you are writing something that is locality relevant.
These days libraries do not have much money to splash about on new books. If yours is free and locally relevant then it will go to the top of their requirements page.
Twenty years ago I wrote and published (hand-made!) a book about a local SSSI (Site of Special Scientific Interest) The book, my first, sold well for a local history book. I ended up making over 250 copies.
But the ones which still give me the greatest thrill are the ones that I gave to local libraries and schools. Believe it or not, twenty years down the line these little books are still in use today.
How do I know this? Well, one of the more sensible things I did at the time was to sign up my book for Public Lending Rights. Consequently I now get a small payment (a couple of quid) every year or so. More on the PLR scheme in another post.
Unfortunately I do not know how libraries view fiction as I have never placed a fiction work with them. But I would suspect that local libraries would view a local author positively whatever the type of book. I would imagine that this is especially true if the author has managed to work some local interest into the story. I have always found the staff in local libraries supportive of local authors. They generally have a passion for literature and usually the local area as well. Drop them an email and find out!
While libraries and the associated PLR will not get you much revenue it will get your name out there. If you write anything with a local theme then I am sure your work will be regarded positively.
As I remember the only requirement that was placed on my book by the local library was that it needed to have an ISBN number. Through talking to other local study authors I understand this may get waived depending on the book and its subject matter. That would be up to the librarian. But really, I would suggest you always publish with an ISBN number anyway.
I posted on Buying ISBN numbers in the UK here. The price for a single ISBN number makes your eyes water. I would recommend buying at least ten.
Libraries are still culturally very important. Make use of them both as resources and as clients.