Have you ever wondered, how much you remember from a book?
Usually, we forget half of what we read after 2 weeks and 90% after 2 months.
A great place to start with book retention is with understanding some key ways our brain stores information.
When you are very impressed by something (an idea, a picture, a sound, a face, a text, a situation), the probability that you will remember it is much higher. For example, if as a child you were left alone lost in a mall for a while, you might remember the whole situation very accurately. Same with your book: if you are very impressed by something the main character did in his journey, the chance you will remember this aspect becomes higher. The good thing is that you can increase the strength of this impression yourself while reading.
For example, you can stop reading one second and picture the situation in your mind, exaggerating some features of the situation in order to enhance the impression of your mental image, by adding violence, greatness, or anything to shock yourself. You can even add yourself into your mental picture, imagining that character thanking you for your help or kicking your butt or anything memorable. This will make the impression stronger.
If you can link something you read to anything you already know, the probability of remembering it becomes even stronger—sometimes incredibly strong. For example, if your favourite character from the book was born on the same day as you, you would find it very easy to remember this because you linked the data you read to something you already know for sure and will not forget. It is like tying something new (the data you read, like birthdays) to a tree (a piece of data you know, your own birthday). That is why the more you know about a topic, the easier it is to learn more and more.
Linking the text to something you already know and prior knowledge, is a great way to build the association.
If you read a book 10 times you will remember more. Same for anything, a recipe, a route between two locations, the lyrics of a song, phone numbers, etc. The more you repeat, the more you remember. When reading a book, if you do not want to read it several times, you can highlight a few parts that you want to remember and re-read only those parts several times. You will remember these segments much better. And you will see that they will also help you remember the rest of the book.
In summary, impress yourself with powerful mental images, make associations with what you already know (and make sure you learn the basics before you learn more), and repeat this exercise several times. Work to become better at remembering and you will become better at remembering everything you want.