A good writer is a good reader, everyone knows that. So read books, read others. You can even read yourself, your own existence is probably the best book there is.
A good reader reads. A great reader reads twice. Once to understand, and once to analyze.
Understanding implies leaving your body to get in the shoes of the author. You must shut down your inner voice and listen with the intent to feel completely, regardless of your own opinions. The first read is a glance of compassion where you must abandon yourself to the moment and the writer.
You cannot make yours what you do not understand. Only when you understand can you truly digest what's being fed to you.
The second read gives you lasting nutrients. It's about tying the micro to the macro, tying what's being said to reality. It starts with identifying the structure of the book: parts, chapters, sections, paragraphs... together they form a delicate meal. Each unit has its flavor, its key takeaways. Writing those down in relation to the overall structure is finding the hidden recipe, the underlying message.
All that's left is for you to come up with your own cooking. Congrats, you're a Chef reader.