Read the textbook passages entirely before you mark them up. This will help you mark only the information you really need.
Use a highlighter to emphasize key facts, terms or headings. Avoid highlighting entire sentences or passages.
Underline the main point of sentences that are relevant to your studying or research using a pen or pencil.
Circle key terms that you need to memorize. This makes finding them in the text easier.
Use a shorthand system for marking key areas of the text. For example, you might write "ex" to stand for example, "mem" to stand for memorize or "def" to stand for definition.
Make notes about the text in the margins. Your notes might be paraphrasing, pulling out key information or reminding yourself how you want to use the information in a paper.