Learn what the textbook contains. Examine the table of contents and see how it is arranged. If it is just a chapter you are dealing with, examine the chapter title, headings and pictures. This exercise will act as a road map to gleaning the required information.
Read chapter summaries and conclusions. These frame the chapter subjects and contain the most important information.
Ask yourself question about the material that seems to be pertinent to the direction of the class. Use the index to find that information. If you do not know what questions to ask, use the review section of each chapter and go through its questions.
Skim the words quickly once and then go back and skim again. As you pick up on information write it down.
Learn definitions. Find new terms the book introduces by finding the italicized words or reviewing the definition or term section at the end of each chapter.
Read the breakouts and supplemental content. This will give you real-world examples that pertain to the subject. It will frame the material in a realistic setting.