Austin Publishing University this past Sunday. Of the many topics covered was how to make the content of your book appealing to an acquisitions editor. Lari Bishop, the managing editor at Greenleaf Book Group said that in order to entice a publisher (and ultimately readers) the content needs to be compelling, marketable, and memorable.
In order to attract readers, the topic or hook of your book needs to be something people are interested in. If you are writing a business book, it needs to be a subject that can improve a professional's business. If you are writing a middle grade novel, the hook needs to be something an 8-12 year old would want to read.
There needs to be enough people interested in your topic in order to justify the cost of developing the book. Publishing and promoting a book takes a great deal of time and money. There's editing, design, printing, warehousing, shipping, publicity, marketing, etc. Be sure you are making it worth their while.
The writing needs to be good. Something about the book needs to stick with the reader after they're done, whether its character development, voice, setting, or a combination of many factors. This is what creates the desire in the reader to tell other people about the book. Word of mouth promotion is essential to the life of a book.
You need to consider all three of these elements before you even start writing. You need to develop your book with the reader in mind and you need to be able to clearly communicate to the publisher who the reader is and how many of them there are. Remember, publishing is a business. You need to approach it with both your business and your artist hat on.