One person telling another about a book is the most powerful form of promotion there is. It can happen on a big scale - the famous examples are Trainspotting and Captain Corelli's Mandolin. But it also happens every day between people in conversation at work, in cafes, on the web. It is the reason borrowers flock round the returns trolley - if somebody else has read it, it must be good.
Libraries are well placed to facilitate reader to reader connection. Comments inside books, readers' noticeboards, readers' websites, bookchains, reading groups - there are plenty of successful ideas which are based on this principle.
Reader to reader expresses an equal relationship. Think of yourself as a reader talking to other readers, not as trying to be an 'expert.' Your talking and writing about books will keep fresh and sharp, avoiding blandness and pomposity, if you keep the reader to reader principle in mind.