Start using the SQ3R method when you read your textbooks. One of your elementary school teachers probably taught you this study technique, but you may not have used it recently. Each letter in SQ3R stands for a step to be followed in your reading. The steps are: survey, question, and the 3R's -- read, recite, and review.
The first step in this method is to survey the material by looking at all the headings and subheadings in the reading assignment. Once you have a general picture of what you are about to read, you're ready to go on.
Q stands for question and involves turning each heading into a question to be answered. You can also make questions for the subheadings. When you write down the questions, be sure to leave some space for your answers. Together, the questions and answers will provide an excellent study sheet for reviewing what you have read. No longer will you need to reread the material.
Begin the 3R's by reading the material under each heading to find the answer to your question. Next, you should recite the answer that you found out loud to help reinforce what you have just learned. Then, write the answer down on your paper. Finally, you need to review your questions and answers before closing the textbook.
Using the SQ3R method will change a passive reader into an active reader. You'll find it easier to stay focused and interested in your reading. Good Luck!