Eliminate distractions. If you have trouble retaining what you read, don't read while watching the nightly news, listening to music, or talking to your roommate. Isolate yourself in a quiet environment and turn off any potential distractions, like your computer, your television or your cell phone. Not worrying about these different things will allow you to concentrate and focus on your reading assignment.
Scan the content before you read. Before you read a chapter of a textbook, flip through the pages and read the headings and subheadings and glance at the charts or pictures to give yourself an idea of the information you'll be learning as you read. This will get your mind on the right track and give you an idea of where all the information you're absorbing is headed.
Activate your imagination as you read. If possible, imagine yourself in the situations you're reading about or try to visualize what the words on the page are describing. Visualizing the material, rather than staring at black letters on a white page, will increase your comprehension of the subject matter
Recite difficult-to-understand passages out loud. If you come across a sentence or paragraph that doesn't make sense to you, read it slowly, giving your mind the chance to digest and process each word as you speak it.
Take notes or highlight important facts as you read. Involving your hands and writing the information down reinforces the knowledge you've just gained and improves your memory. It also gives you something to go back and look at later while you're studying for a quiz or a test.