Take some time on your description, they may use it when they list your book. If you give a quick, jumbled description, chances are pretty good that they won't download it, much less read it. Use your head. Yes, marketing is a popular subject, with a huge following. The answer to that is to specialize.
Doctors do it.
For instance, if you're knowledgeable about search engines, write a book on each of them. Make it a series. There are 8 major search engines. We all want to place well on them, but few of us have the time or desire to learn about all of them in one setting. It quickly becomes overwhelming.