I use this method since I was a University student:
The same time I'm reading a book I'm taking notes in a mindmap following the next rules:

1. Write the book's title in the center of mindmap
2. Create a branch with book's general info [Writer, Publishing House etc]
3. For each book's chapter create a different branch using its title
4. For each chapter's branch write sub-chapters titles
5. If there are any important info you have to remember, just put it on the appropriate branch.