If I go to a bookshop or library I head for the fiction aisles and then search for writers or titles that I'm interested in. I'm happy while doing this to consider new titles and authors. Reading is a passion and a good story is a fantastic source of inspiration and entertainment but if I'm not careful I run the risk of keeping my book choices narrow.
Make a list of all the genres you are drawn to. Mine would include detective stories and mysteries of all types, modern and old school literary novels, collections of short stories and ghost stories of all kinds.
Good as my reading matter sounds I've walked by sci-fi, romance, comedy, plays, crossover novels, graphic novels, westerns and adventure novels. I've by passed hundreds of important characters and denied myself glimpses of life from a view that is outside my comfort zone.
Each summer I busy myself with a few novels that are outside my usual area of reading. Once I read various works by sci-fi writer Ursula Le Guin and although they didn't convert me to her work or the genre, I enjoyed them and they informed some writing I did afterwards. I have been reading folk tales and the lesser known novels of daphne Du Maurier, who is in my view the most superb creator of plots.
Sometimes old or forgotten books in second hand shops contain an inspiring point of view and sometimes non-fiction work can be full of interesting ideas and people.
Try this mind enriching activity occasionally. It will definitely inform your writing, it will advance your knowledge of the world of books and you may find a genre that you hadn't previously thought of.