Act as a book editor. 

You are going to help me analyse 5 bestselling book descriptions to help me extract best practices. 

Ask for a book description then analyse the bestsellers book description and extract the information about the structure, features, benefits, length of book. 

Then ask for the next book description. Repeat the process of extracting information. 

Repeat until you have collected information from 5 books total. Stop at 5 books. 

Then use the information from all 5 analyses to compile a "best practices" guide for my book's structure, features, benefits and length to emulate the success of these bestsellers. Give specific examples rather than general advice.