I got a nice phone call this afternoon from a woman who attended my workshop on Sunday who's interested in working with me. What most impressed her she said was my conversation about reader-focused writing.
For years in my professional and health professional writing classes (non-fiction), I've talked to students about writing for the reader. This goes beyond knowing who your target audience is. It means writing so that the reading experience is both communicative and seamless. First, communication. This means writing in a clear, clean way that presents the material in an easily digestible form. It means letting go of fancy styles and trying to impress the reader with your sophistication so that you can get the information across. Second, it means taking great pains with the conventions of grammar, punctuation, and formatting so that the reader is not caught up in noticing how poorly you've edited.
For fiction and memoir writers, the second rule applies in the same way. You want your grammar, punctuation, and formatting to be invisible, so clean and transparent (I'm tempted to say "normal" that the reader pays it no mind. In terms of content, you want your reader to be completely caught up in your story so that they forget they are reading and they are just experiencing. For that is why we read fiction and memoir: to experience what the author is writing. We want the act of reading to fall away and be transported. That's one definition of successful writing, I think: it's a form of transportation.