I have always thought that the clever chap is the one who steals someone elses idea and brings it up to date. What is important today is not what book categories are selling well, but what subjects people are searching for on the internet. Identify them, incorporate them and you are on your way to your first million in the time it takes to say Tyson Beckford (who's he you ask, just be patient I reply).
Now those wonderful people at Google (Note to Google people, remember me, I once asked you to give me a job, that was nine months ago and I haven't heard anything yet) make life easy for you by providing a list of all the most popular search phrases used on the Google search engine. These are published and constantly updated on a site called Google Trends. When I checked the list earlier today the top seven were as follows :
1. People Magazine Sexiest Fan Contest
2. Tyson Beckford
3. Fernan Leger, Cubist Painter
4. Pituitary Adenoma
5. Capistrano School District
6. 200 Cigarettes
7. HIV Cure.
I acknowledge that this is a somewhat strange mixture, but if those nice people from Google tell us this is the list, this is the list. All that is then needed is to get images from these themes and incorporate them into your book cover. So take images of the shortlisted candidates from People Magazine's competition, add Tyson Beckford (who appears to be an actor), blend in a picture of a school in Capistrano, a poster for the film 200 Cigarettes, a painting by Leger, an HIV virus and a diagram of the pituitary gland, and add in some old text you might have composed ten years ago and forgot about because it was so boring.
What you get is my latest book. Now available exclusively from this site. Only £20 for a signed copy. Now, you see, I'm not quite as daft as you thought I was.