3. Mystery
In a mystery novel, the most important thing is how you present the crime somewhere in the beginning of the book, and then research the methods of committing the crime giving your readers clues to solve it themselves. It is supposed to be fun and easy to read, but not too easy or it will cause the reader to lose interest. If you have some good ideas for a mystery story, then why not? It might not be so difficult to write it after all.