You definitely do learn a lot while reading. You may be a moderate or voracious reader. As life is a learning process so is reading. Every book is a new and different experience. Books are a treasure trove of information. As you read along you assimilate and absorb the contents and the theme. Likewise you come across new words and sentences that describe the situations with clarity and purpose.
But are you able to retain it to memory and utilize your reading experience for a practical purpose? The book may be absorbing and you may never feel like putting it down. The point I am trying to make is that never let your reading experience go waste. Reading helps you enrich your word power and communication abilities.
But do not reduce reading to an academic exercise. This way you are never going to achieve your objective. You are into the habit of reading. Good. You find what you are reading to be interesting and you are totally absorbed in the book. Fantastic! Since you now have the foundation for enriching your word power.
From here onwards you need to develop a certain method to ensure that you make the best possible use of your reading habit. Again, I would like to emphasize that your approach should not be academic. This kind of approach may prove to be a spoilsport and deprives you of a fun filled learning experience.