Here’s an interesting post entitled 20 Rules for Writing Detective Stories by S.S. Van Dine (found on the website Socialpolitan: Fiction Writing Craft). They are useful and interesting rules, but the most important lesson to be learned from them is this:
When writing genre fiction of any kind, keep in mind the opinions, likes and dislikes of the Rabid Fans of your genre. I’m not saying you have to cater to them necessarily, but if you’re looking for popularity and love from the crowd who follow your genre, you have to know what they like!
Always remember there are fans out there who take their Genre very, very seriously. As a writer you may or may not be as obsessive on the topic as they are, but you should at least listen to them. A bit.
These rules are also a healthy reminder not to take the easy way out when faced with a plot problem. Being even a little lazy when concocting your story can leave your readers feeling totally ripped off.