Are you a book lover? Is reading one of your favourite past-times? Are there authors whose work you adore?
You can help them by writing a review.
Writing a review aids both authors and publishers. This can be the case even if you didn't like the book, especially if you include reasons that let them know what pleased you or what disappointed you. It is helpful to hear that kind of feedback as it gives authors and publishers an idea of what they are doing right and what they are doing wrong.
While everyone's experience with a book is subjective, it can still assist us to know what it is about a book that made you like it so much, or why the book you found so difficult to read was such a struggle for you.
There are a number of sites now where you can publish reviews, such as Amazon, Goodreads, Shelfari and BookLikes. Leaving reviews at any or all of them, especially for your favourite books, is a great help, as then others can see your review and might try that book themselves, which means more people will have the opportunity to read it.
When writing a review, you can start with a quick overview of the story, but it's best to keep this brief. After all, people can find out what the book is about by reading the blurb on the back. Certainly, don't make your review more overview than comment. Your comment section doesn't have to be long. Put down what you liked most about the book and anything you didn't like. Let other readers know why they should try this book.
This is one of the most effective ways you can get the word out about your favourite books.