I recommend that all writers, whether you intend to self-publish or publish traditionally, read the excellent and short reviews of self-published books that Jefferson Smith (and occasional guest reviewers) posts at Immerse or Die. Smith maintains that the most important quality of fiction is whether it enables the reader to become immersed in the story, an assertion with which I wholeheartedly agree. This is the elusive quality of suspension of disbelief, that ability to forget you’re reading about made-up places and characters, and to instead actually believe that what you’re reading could have really happened to these real people. This is why we readers want to read.
In his reviews Smith explains exactly why his immersion was broken (or less often, not broken) by the book he is reviewing. His clear and precise explanations have helped me pinpoint exactly what I disliked about the self-published books I have been reviewing. They should be very instructive to writers as what not to do.
Nothing will kill your story faster than grammatical errors and superfluous typos. Believe it!