As a published case author, here are my top 10 tips for writing great cases:
1. Choose an interesting topic. The best cases are ones that are relevant to a number of businesses, current, and have no clear cut answer.
2. Do your research (see box on the side!)
3. Think of your case like a meal. It should have an appetizer, an entree and a dessert at the very least.
4. Engage your readers with a well thought out and entertaining narrative. Don't be afraid to write colloquially or informally.
5. Grab your audience with catch section headings. HBS' influence on case authoring has made this sort of obligatory!
6. Have exhibits or appendices that require interpretation.
7. Try to show many sides of a position or possible courses of action. Give your reader choices. Don't steer them in one direction or another no matter how strongly you may feel about a particular course of action.
8. Discussion questions should be thought provoking and open ended. But not more than 4-6 of them max.
9. Consider active learning options in your teaching notes.
10. No matter how serious the topic, leave room for humor!