If you are interested in web site design, you may have come across the tutorial pages at Yale University's Centre for Advanced Instructional Media. The tutorial is in Adobe's PDF format, the files are very big, and it's rather a loooooooong download. So now they've published it in book form.
Every page is packed with good advice.
Describing murder is not. Sex is a not a crime, but describing it is. The following requirements were laid down by the editors of 'Spicy Detective'. In describing the breasts of a female character, avoid anatomical descriptions. If it is necessary for the story to have a girl give herself to a man, or to be taken by him, do not go too carefully into the details.