I think some of the best advice I've been given is to create tension on every page. I got this from one of Donald Maas' books.
This led to my first rule of writing crime fiction: Never bore the reader. That means there needs to be figurative thunder and lightning on every page. It can be overt or subtle, physical or psychological, and without a doubt it can be real or perceived. But in all cases it means making your protagonist's position become more and more precarious right up until the case is solved and maybe beyond.
In my world, there are three major skills a crime writer needs. The first is being a natural story teller. The second is understanding how stories (novels or short stories) are put together. With crime fiction there is a rather rigid ways to structure a story. The third skill is an understanding of grammar and punctuation.
This led to the second rule of crime fiction: Get an editor with complimentary skills. In my case, I'm good with skill number one, adequate with number two, and totally inadequate with number three. Fortunately, my editor is great with three, good with two, and not interested in one. We work well togehter
On Barry Eisler's website, http://barryeisler.com/index.php, there's a section called MIstakes. Readers can communicate directly with Barry when they find errors in his work. Excellent idea that I will incorporate in my website (when I get it finished - soon, I promise).
This supports my third rule: Readers are really, really smart; don't try to fool them. This means you have to do your research. In the days of paper books, writers wrote and reader read. Now we interact to improve our work. Make sure you know what you're talking about. Go to the places where you set scenes. Don't try to set a story in Budapest when you've never been out of Arkansas. You must understand how people react in various situations. How will a young woman react if she is kissed by a stranger and how will that change the story line? You must let the characters drive the story. If you don't do these things our readers will correct you, which is still better than having them never buying your books again.
Dang, I love this ebook world!
Do you have rules?