Read the introduction. Most introductions provide detailed chapter information that can help guide you through the book. It will typically paraphrase main conclusions the author is making in the text. By looking at the various chapters, you will likely be able to identify chapters and data that are most pertinent.
Look over the Preface, front and back cover, Table of Contents, pictures, charts, headings and Conclusion. This can give you a solid picture of the main theme of the book. These often contain more information than the actual body text and provide a look at the progression of the text.
Read about the author. They are humans like the rest of us with their biases and backgrounds.
Take notes. Whether you ever refer back to them is not the point. What you are doing by taking notes is processing the input from your reading and you have a much higher chance of remembering what you have read. This is not about highlighting text. Write notes on paper or in the margins clarifying concepts. Write whether you agree or disagree and why, if it is appropriate to the subject. Compare the information with other texts regarding the same topic.
Stop at the end of each page and ask yourself if you understood what was written. Write a couple of brief sentences summarizing what you have read. Reading for academics means making sure that you comprehend the material.
Talk with others about what you have read. This allows you the opportunity to verbalize what is rolling around in your head.
Draw pictures to clarify or look for analogies in the world that will help create a better understanding.
Write down questions that pop up. Don't let uncertainties stop you. As you move forward in your reading, the answer to the very question you wrote down may fall into place.
Read the conclusion again. Look for anything you may have missed in your reading that could be significant to your comprehension of the material.
Spend some time between reading sessions allowing your unconscious mind to process and work with the information.