There's no doubt that for any bookstore to thrive in this neighborhood it must serve the neighborhood. As the previous poster suggested, stocking a solid range of classic and contemporary books in Spanish and South Asian languages would be necessary, along with a focused selection of English-language titles that run from romance and thrillers to literary fiction.
But more than the actual books, I really believe that in Jackson Heights a bookstore would also have to involve the community with readings, workshops, story hours, whatever. I've been to readings at Terraza where it is nothing but Argentine poets. Because Jackson Heights is such a diverse neighborhood, a bookstore could really focus on cultivating all sorts of internationally-minded literary events, which if done correctly could make the store a destination.
I've lurked here long enough to know some of you really dislike the idea of Jackson Heights "becoming like Brooklyn," but if you look at the popular indie bookstores in Brooklyn today -- Word in Greenpoint; Book Court in Boerum Hill; Greenlight in Fort Greene -- they cater to their neighborhoods, and in doing so have facilitated book cultures that attract neighbors and folks from all over the city because of the programs they schedule. It doesn't matter what you think of these stores, these neighborhoods and their residents. What's important is the model of considering the community at large and involving it.
If someone with the wherewithal and capital comes along thinking along these lines I believe a bookstore would thrive in Jackson Heights.